description: You are given strings S and T, consisting of lowercase English letters. It is guaranteed that T is a permutation of the string abc. 
  
  Find string S', the lexicographically smallest permutation of S such that T is not a subsequence of S'.
  
  String a is a permutation of string b if the number of occurrences of each distinct character is the same in both strings.
  
  A string a is a subsequence of a string b if a can be obtained from b by deletion of several (possibly, zero or all) elements.
  
  A string a is lexicographically smaller than a string b if and only if one of the following holds:
  
    * a is a prefix of b, but a ≠ b;
    * in the first position where a and b differ, the string a has a letter that appears earlier in the alphabet than the corresponding letter in b.
  
  Input
  
  Each test contains multiple test cases. The first line contains a single integer t (1 ≤ t ≤ 1000) — the number of test cases. Description of the test cases follows.
  
  The first line of each test case contains a string S (1 ≤ |S| ≤ 100), consisting of lowercase English letters.
  
  The second line of each test case contains a string T that is a permutation of the string abc. (Hence, |T| = 3).
  
  Note that there is no limit on the sum of |S| across all test cases.
  
  Output
  
  For each test case, output a single string S', the lexicographically smallest permutation of S such that T is not a subsequence of S'.
  
  Example
  
  Input
  
  
  7
  abacaba
  abc
  cccba
  acb
  dbsic
  bac
  abracadabra
  abc
  dddddddddddd
  cba
  bbc
  abc
  ac
  abc
  
  
  Output
  
  
  aaaacbb
  abccc
  bcdis
  aaaaacbbdrr
  dddddddddddd
  bbc
  ac
  
  Note
  
  In the first test case, both aaaabbc and aaaabcb are lexicographically smaller than aaaacbb, but they contain abc as a subsequence.
  
  In the second test case, abccc is the smallest permutation of cccba and does not contain acb as a subsequence.
  
  In the third test case, bcdis is the smallest permutation of dbsic and does not contain bac as a subsequence.
solution: import java.util.*;
  import java.io.*;
  import java.math.*;
  
  
  /**
   * @author Naitik
   * 
   */
  public class Main
  
  { 
  	 static FastReader sc=new FastReader(); 
  	 static long dp[];
  	 //static int v[][];
  //	 static int mod=998244353;;
  	 static int mod=1000000007;
  	 static int max;
  	 static int bit[];
  	 //static long fact[];
  //	 static long A[];
  	// static TreeMap<Integer,Integer> map;
  	 //static StringBuffer sb=new StringBuffer("");
  	 static HashMap<Integer,Integer> map;
  	   static PrintWriter out=new PrintWriter(System.out);
  	  public static void main(String[] args)
  	  {
  		 //  StringBuffer sb=new StringBuffer("");
  		  int ttt=1;
  		       ttt =i();	
  	        outer :while (ttt-- > 0) 
  			{
  	        	String s=s();
  	        	String t=s();
  	        	String y="abc";
  	        	s=sort(s);
  	        	if(!t.equals(y)) {
  	        		out.println(s);
  	        		continue outer;
  	        	}
  	        	int a=0,b=0,c=0;
  	        	char A[]=s.toCharArray();
  	        	for(char ch : A) {
  	        		if(ch=='a') {
  	        			a++;
  	        		}
  	        		else  if(ch=='b') {
  	        			b++;
  	        		}
  	        		else if(ch=='c') {
  	        			c++;
  	        		}
  	        	}
  	        	
  	        	if(a==0 || b==0 || c==0) {
  	        		out.println(s);
  	        		continue outer;
  	        	}
  	        	while(a>0) {
  	        		out.print('a');
  	        		a--;
  	        	}
  	        	while(c>0) {
  	        		out.print('c');
  	        		c--;
  	        	}
  	        	while(b>0) {
  	        		out.print('b');
  	        		b--;
  	        	}
  	        	for(int i=0;i<A.length;i++) {
  	        		if(A[i]=='a' || A[i]=='b' || A[i]=='c') {
  	        			continue;
  	        		}
  	        		out.print(A[i]);
  	        	}
  	        	out.println();
  	        	
  	        	
  	        }
  	        //System.out.println(sb.toString());
  		     out.close();
  	     
  	     
  	    //CHECK FOR N=1                    //CHECK FOR M=0
          //CHECK FOR N=1                    //CHECK FOR M=0
         	//CHECK FOR N=1
         	
  		        
  		     
      }
  	
  	 
  	  
  static class Pair implements Comparable<Pair>
       {
      	 int x;
      	 int y;
      	 int z;
      	 Pair(int x,int y,int z){
      		 this.x=x;
      		 this.y=y;
      		 this.z=z;
      		 
      	 }
  		@Override
  		public int compareTo(Pair o) {
  			if(this.x>o.x)
  				return 1;
  			else if(this.x<o.x)
  				return -1;
  			else {
  				if(this.y>o.y)
  					return 1;
  				else if(this.y<o.y)
  					return -1;
  				else
  					return 0;
  			}
  		}
  //		public int hashCode() 
  //		{ 
  //			final int temp = 14; 
  //			int ans = 1; 
  //			ans =x*31+y*13; 
  //			return ans; 
  //		} 
  //		@Override
  //		public boolean equals(Object o) 
  //		{ 
  //			if (this == o) { 
  //				return true; 
  //			} 
  //			if (o == null) { 
  //				return false; 
  //			} 
  //			if (this.getClass() != o.getClass()) { 
  //				return false; 
  //			} 
  //			Pair other = (Pair)o; 
  //			if (this.x != other.x || this.y!=other.y) { 
  //				return false; 
  //			} 
  //			return true; 
  //		} 	
  //		
  		/* FOR TREE MAP PAIR USE */
  		
  //		public int compareTo(Pair o) {
  // 			if (x > o.x) {
  // 				return 1;
  // 			}
  // 			if (x < o.x) {
  // 				return -1;
  // 			}
  // 			if (y > o.y) {
  // 				return 1;
  // 			}
  // 			if (y < o.y) {
  // 				return -1;
  // 			}
  // 			return 0;
  // 		}
  		
       }
  
  static int find(int A[],int a) {
  	  if(A[a]==a)
  		  return a;
  	  return A[a]=find(A, A[a]);
  }
  //static int find(int A[],int a) {
  //	  if(A[a]==a)
  //		  return a;
  //	  return find(A, A[a]);
  //}
  //FENWICK TREE
  static void update(int i, int x){
  	for(; i < bit.length; i += (i&-i))
  		bit[i] += x;
  }
  
  static int sum(int i){
  	int ans = 0;
  	for(; i > 0; i -= (i&-i))
  		ans += bit[i];
  	return ans;
  }
  //END
  static void add(int v) {
  	if(!map.containsKey(v)) {
  		map.put(v, 1);
  	}
  	else {
  		map.put(v, map.get(v)+1);
  	}
  }
  static void remove(int v) {
  	if(map.containsKey(v)) {
  		map.put(v, map.get(v)-1);
  		if(map.get(v)==0)
  			map.remove(v);
  	}
  }
  public static int upper(int A[],int k,int si,int ei)
  {
  	int l=si;
  	int u=ei;
  	int ans=-1;
  	while(l<=u) {
  		int mid=(l+u)/2;
  		if(A[mid]<=k) {
  			ans=mid;
  			l=mid+1;
  		}
  		else {
  			u=mid-1;
  		}
  	}
  	return ans;
  }
  public static int lower(int A[],int k,int si,int ei)
  {
  	int l=si;
  	int u=ei;
  	int ans=-1;
  	while(l<=u) {
  		int mid=(l+u)/2;
  		if(A[mid]<=k) {
  			l=mid+1;
  		}
  		else {
  			ans=mid;
  			u=mid-1;
  		}
  	}
  	return ans;
  	
      
  }
  static int[] copy(int A[]) {
  	int B[]=new int[A.length];
  	for(int i=0;i<A.length;i++) {
  		B[i]=A[i];
  	}
  	return B;
  }
  static long[] copy(long A[]) {
  	long B[]=new long[A.length];
  	for(int i=0;i<A.length;i++) {
  		B[i]=A[i];
  	}
  	return B;
  }
  static int[] input(int n) {
  	int A[]=new int[n];
  	   for(int i=0;i<n;i++) {
  		   A[i]=sc.nextInt();
  	   }
  	   return A;
     }
  static long[] inputL(int n) {
  	long A[]=new long[n];
  	   for(int i=0;i<n;i++) {
  		   A[i]=sc.nextLong();
  	   }
  	   return A;
     }
  static String[] inputS(int n) {
  	String A[]=new String[n];
  	   for(int i=0;i<n;i++) {
  		   A[i]=sc.next();
  	   }
  	   return A;
     }
  static long sum(int A[]) {
  	long sum=0;
  	for(int i : A) {
  		sum+=i;
  	}
  	return sum;
  }
  static long sum(long A[]) {
  	long sum=0;
  	for(long i : A) {
  		sum+=i;
  	}
  	return sum;
  }
  static void reverse(long A[]) {
  	int n=A.length;
  	long B[]=new long[n];
  	for(int i=0;i<n;i++) {
  		B[i]=A[n-i-1];
  	}
  	for(int i=0;i<n;i++)
  		A[i]=B[i];
  	
  }
  static void reverse(int A[]) {
  	int n=A.length;
  	int B[]=new int[n];
  	for(int i=0;i<n;i++) {
  		B[i]=A[n-i-1];
  	}
  	for(int i=0;i<n;i++)
  		A[i]=B[i];
  	
  }
  static void input(int A[],int B[]) {
  	   for(int i=0;i<A.length;i++) {
  		   A[i]=sc.nextInt();
  		   B[i]=sc.nextInt();
  	   }
  }
  static int[][] input(int n,int m){
  	int A[][]=new int[n][m];
  	for(int i=0;i<n;i++) {
  		for(int j=0;j<m;j++) {
  			A[i][j]=i();
  		}
  	}
  	return A;
  }
  static char[][] charinput(int n,int m){
  	char A[][]=new char[n][m];
  	for(int i=0;i<n;i++) {
  		String s=s();
  		for(int j=0;j<m;j++) {
  			A[i][j]=s.charAt(j);
  		}
  	}
  	return A;
  }
  static int nextPowerOf2(int n)
  {
      n--;
      n |= n >> 1;
      n |= n >> 2;
      n |= n >> 4;
      n |= n >> 8;
      n |= n >> 16;
      n++;
       
      return n;
  }
  static int highestPowerof2(int x)
  {
     
      x |= x >> 1;
      x |= x >> 2;
      x |= x >> 4;
      x |= x >> 8;
      x |= x >> 16;
       
      return x ^ (x >> 1); 
   
  }
  static long highestPowerof2(long x)
  {
     
      x |= x >> 1;
      x |= x >> 2;
      x |= x >> 4;
      x |= x >> 8;
      x |= x >> 16;
      return x ^ (x >> 1); 
   
  }
  
  static int max(int A[]) {
  	int max=Integer.MIN_VALUE;
  	for(int i=0;i<A.length;i++) {
  		max=Math.max(max, A[i]);
  	}
  	return max;
  }
  static int min(int A[]) {
  	int min=Integer.MAX_VALUE;
  	for(int i=0;i<A.length;i++) {
  		min=Math.min(min, A[i]);
  	}
  	return min;
  }
  static long max(long A[]) {
  	long max=Long.MIN_VALUE;
  	for(int i=0;i<A.length;i++) {
  		max=Math.max(max, A[i]);
  	}
  	return max;
  }
  static long min(long A[]) {
  	long min=Long.MAX_VALUE;
  	for(int i=0;i<A.length;i++) {
  		min=Math.min(min, A[i]);
  	}
  	return min;
  }
  static long [] prefix(long A[]) {
  	long p[]=new long[A.length];
  	p[0]=A[0];
  	for(int i=1;i<A.length;i++)
  		p[i]=p[i-1]+A[i];
  	return p;
  }
  static long [] prefix(int A[]) {
  	long p[]=new long[A.length];
  	p[0]=A[0];
  	for(int i=1;i<A.length;i++)
  		p[i]=p[i-1]+A[i];
  	return p;
  }
  static long [] suffix(long A[]) {
  	long p[]=new long[A.length];
  	p[A.length-1]=A[A.length-1];
  	for(int i=A.length-2;i>=0;i--)
  		p[i]=p[i+1]+A[i];
  	return p;
  }
  static long [] suffix(int A[]) {
  	long p[]=new long[A.length];
  	p[A.length-1]=A[A.length-1];
  	for(int i=A.length-2;i>=0;i--)
  		p[i]=p[i+1]+A[i];
  	return p;
  }
  static void fill(int dp[]) {
  	Arrays.fill(dp, -1);
  }
  static void fill(int dp[][]) {
  	for(int i=0;i<dp.length;i++)
  	Arrays.fill(dp[i], -1);
  }
  static void fill(int dp[][][]) {
  	for(int i=0;i<dp.length;i++) {
  		for(int j=0;j<dp[0].length;j++) {
  			Arrays.fill(dp[i][j],-1);
  		}
  	}
  }
  static void fill(int dp[][][][]) {
  	for(int i=0;i<dp.length;i++) {
  		for(int j=0;j<dp[0].length;j++) {
  			for(int k=0;k<dp[0][0].length;k++) {
  			Arrays.fill(dp[i][j][k],-1);
  			}
  		}
  	}
  }
  static void fill(long dp[]) {
  	Arrays.fill(dp, -1);
  }
  static void fill(long dp[][]) {
  	for(int i=0;i<dp.length;i++)
  	Arrays.fill(dp[i], -1);
  }
  static void fill(long dp[][][]) {
  	for(int i=0;i<dp.length;i++) {
  		for(int j=0;j<dp[0].length;j++) {
  			Arrays.fill(dp[i][j],-1);
  		}
  	}
  }
  static void fill(long dp[][][][]) {
  	for(int i=0;i<dp.length;i++) {
  		for(int j=0;j<dp[0].length;j++) {
  			for(int k=0;k<dp[0][0].length;k++) {
  			Arrays.fill(dp[i][j][k],-1);
  			}
  		}
  	}
  }
  static int min(int a,int b) {
  	return Math.min(a, b);
  }
  static int min(int a,int b,int c) {
  	return Math.min(a, Math.min(b, c));
  }
  static int min(int a,int b,int c,int d) {
  	return Math.min(a, Math.min(b, Math.min(c, d)));
  }
  static int max(int a,int b) {
  	return Math.max(a, b);
  }
  static int max(int a,int b,int c) {
  	return Math.max(a, Math.max(b, c));
  }
  static int max(int a,int b,int c,int d) {
  	return Math.max(a, Math.max(b, Math.max(c, d)));
  }
  static long min(long a,long b) {
  	return Math.min(a, b);
  }
  static long min(long a,long b,long c) {
  	return Math.min(a, Math.min(b, c));
  }
  static long min(long a,long b,long c,long d) {
  	return Math.min(a, Math.min(b, Math.min(c, d)));
  }
  static long max(long a,long b) {
  	return Math.max(a, b);
  }
  static long max(long a,long b,long c) {
  	return Math.max(a, Math.max(b, c));
  }
  static long max(long a,long b,long c,long d) {
  	return Math.max(a, Math.max(b, Math.max(c, d)));
  }
  
  static long power(long x, long y, long p)
  {
  
  	if(y==0)
  		return 1;
  	if(x==0)
  		return 0;
      long res = 1;
      x = x % p;
  
      while (y > 0) {
  
          if (y % 2 == 1)
              res = (res * x) % p;
  
          y = y >> 1; 
          x = (x * x) % p;
      }
  
      return res;
  }
  static long power(long x, long y)
  {
  
  	if(y==0)
  		return 1;
  	if(x==0)
  		return 0;
      long res = 1;
  
      while (y > 0) {
  
          if (y % 2 == 1)
              res = (res * x);
  
          y = y >> 1; 
          x = (x * x);
      }
  
      return res;
  }
  static void print(int A[]) {
  	for(int i : A) {
  		System.out.print(i+" ");
  	}
  	System.out.println();
  }
  static void print(long A[]) {
  	for(long i : A) {
  		System.out.print(i+" ");
  	}
  	System.out.println();
  }
  static long mod(long x) {
  	  return ((x%mod + mod)%mod);
  }
  static String reverse(String s) {
  	StringBuffer p=new StringBuffer(s);
  	p.reverse();
  	return p.toString();
  }
  
       static int i() {
      	 return sc.nextInt();
       }
       static String s() {
      	 return sc.next();
       }
       static long l() {
      	 return sc.nextLong();
       }  
       static void sort(int[] A){
          int n = A.length;
          Random rnd = new Random();
          for(int i=0; i<n; ++i){
              int tmp = A[i];
              int randomPos = i + rnd.nextInt(n-i);
              A[i] = A[randomPos];
              A[randomPos] = tmp;
          }
          Arrays.sort(A);
       }
       static void sort(long[] A){
  	        int n = A.length;
  	        Random rnd = new Random();
  	        for(int i=0; i<n; ++i){
  	            long tmp = A[i];
  	            int randomPos = i + rnd.nextInt(n-i);
  	            A[i] = A[randomPos];
  	            A[randomPos] = tmp;
  	        }
  	        Arrays.sort(A);
  	     }
    static String sort(String s) {
   	 Character ch[]=new Character[s.length()];
   	 for(int i=0;i<s.length();i++) {
   		 ch[i]=s.charAt(i);
   	 }
   	 Arrays.sort(ch);
   	 StringBuffer st=new StringBuffer("");
   	 for(int i=0;i<s.length();i++) {
   		 st.append(ch[i]);
   	 }
   	 return st.toString();
    }
    static HashMap<Integer,Integer> hash(int A[]){
  	  HashMap<Integer,Integer> map=new HashMap<Integer, Integer>();
  	  for(int i : A) {
  		  if(map.containsKey(i)) {
  			  map.put(i, map.get(i)+1);
  		  }
  		  else {
  			  map.put(i, 1);
  		  }
  	  }
  	  return map;
    }
    static HashMap<Long,Integer> hash(long A[]){
  	  HashMap<Long,Integer> map=new HashMap<Long, Integer>();
  	  for(long i : A) {
  		  if(map.containsKey(i)) {
  			  map.put(i, map.get(i)+1);
  		  }
  		  else {
  			  map.put(i, 1);
  		  }
  	  }
  	  return map;
    }
    static TreeMap<Integer,Integer> tree(int A[]){
  	  TreeMap<Integer,Integer> map=new TreeMap<Integer, Integer>();
  	  for(int i : A) {
  		  if(map.containsKey(i)) {
  			  map.put(i, map.get(i)+1);
  		  }
  		  else {
  			  map.put(i, 1);
  		  }
  	  }
  	  return map;
    }
    static TreeMap<Long,Integer> tree(long A[]){
  	  TreeMap<Long,Integer> map=new TreeMap<Long, Integer>();
  	  for(long i : A) {
  		  if(map.containsKey(i)) {
  			  map.put(i, map.get(i)+1);
  		  }
  		  else {
  			  map.put(i, 1);
  		  }
  	  }
  	  return map;
    }
       static boolean prime(int n) 
  	    { 
  	        if (n <= 1) 
  	            return false; 
  	        if (n <= 3) 
  	            return true; 
  	        if (n % 2 == 0 || n % 3 == 0) 
  	            return false; 
  	        double sq=Math.sqrt(n);
  	  
  	        for (int i = 5; i <= sq; i = i + 6) 
  	            if (n % i == 0 || n % (i + 2) == 0) 
  	                return false; 
  	        return true; 
  	    } 
       static boolean prime(long n) 
  	    { 
  	        if (n <= 1) 
  	            return false; 
  	        if (n <= 3) 
  	            return true; 
  	        if (n % 2 == 0 || n % 3 == 0) 
  	            return false; 
  	        double sq=Math.sqrt(n);
  	  
  	        for (int i = 5; i <= sq; i = i + 6) 
  	            if (n % i == 0 || n % (i + 2) == 0) 
  	                return false; 
  	        return true; 
  	    } 
       static int gcd(int a, int b) 
       { 
           if (a == 0) 
               return b; 
           return gcd(b % a, a); 
       } 
       static long gcd(long a, long b) 
       { 
           if (a == 0) 
               return b; 
           return gcd(b % a, a); 
       } 
       
          
      static class FastReader 
      { 
          BufferedReader br; 
          StringTokenizer st; 
    
          public FastReader() 
          { 
              br = new BufferedReader(new
                       InputStreamReader(System.in)); 
          } 
    
          String next() 
          { 
              while (st == null || !st.hasMoreElements()) 
              { 
                  try
                  { 
                      st = new StringTokenizer(br.readLine()); 
                  } 
                  catch (IOException  e) 
                  { 
                      e.printStackTrace(); 
                  } 
              } 
              return st.nextToken(); 
          } 
    
          int nextInt() 
          { 
              return Integer.parseInt(next()); 
          } 
    
          long nextLong() 
          { 
              return Long.parseLong(next()); 
          } 
    
          double nextDouble() 
          { 
              return Double.parseDouble(next()); 
          } 
    
          String nextLine() 
          { 
              String str = ""; 
              try
              { 
                  str = br.readLine(); 
              } 
              catch (IOException e) 
              { 
                  e.printStackTrace(); 
              } 
              return str; 
          } 
      } 
  } 
  
  
  
  