Vasya is currently at a car rental service, and he wants to reach cinema. The film he has bought a ticket for starts in t minutes. There is a straight road of length s from the service to the cinema. Let's introduce a coordinate system so that the car rental service is at the point 0, and the cinema is at the point s.

There are k gas stations along the road, and at each of them you can fill a car with any amount of fuel for free! Consider that this operation doesn't take any time, i.e. is carried out instantly.

There are n cars in the rental service, i-th of them is characterized with two integers ci and vi — the price of this car rent and the capacity of its fuel tank in liters. It's not allowed to fuel a car with more fuel than its tank capacity vi. All cars are completely fueled at the car rental service.

Each of the cars can be driven in one of two speed modes: normal or accelerated. In the normal mode a car covers 1 kilometer in 2 minutes, and consumes 1 liter of fuel. In the accelerated mode a car covers 1 kilometer in 1 minutes, but consumes 2 liters of fuel. The driving mode can be changed at any moment and any number of times.

Your task is to choose a car with minimum price such that Vasya can reach the cinema before the show starts, i.e. not later than in t minutes. Assume that all cars are completely fueled initially.

Input

The first line contains four positive integers n, k, s and t (1 ≤ n ≤ 2·105, 1 ≤ k ≤ 2·105, 2 ≤ s ≤ 109, 1 ≤ t ≤ 2·109) — the number of cars at the car rental service, the number of gas stations along the road, the length of the road and the time in which the film starts. 

Each of the next n lines contains two positive integers ci and vi (1 ≤ ci, vi ≤ 109) — the price of the i-th car and its fuel tank capacity.

The next line contains k distinct integers g1, g2, ..., gk (1 ≤ gi ≤ s - 1) — the positions of the gas stations on the road in arbitrary order.

Output

Print the minimum rent price of an appropriate car, i.e. such car that Vasya will be able to reach the cinema before the film starts (not later than in t minutes). If there is no appropriate car, print -1.

Examples

Input

3 1 8 10
10 8
5 7
11 9
3


Output

10


Input

2 2 10 18
10 4
20 6
5 3


Output

20

Note

In the first sample, Vasya can reach the cinema in time using the first or the third cars, but it would be cheaper to choose the first one. Its price is equal to 10, and the capacity of its fuel tank is 8. Then Vasya can drive to the first gas station in the accelerated mode in 3 minutes, spending 6 liters of fuel. After that he can full the tank and cover 2 kilometers in the normal mode in 4 minutes, spending 2 liters of fuel. Finally, he drives in the accelerated mode covering the remaining 3 kilometers in 3 minutes and spending 6 liters of fuel. 

import java.util.*;
import java.io.*;
import java.math.*;


/**
 * @author Naitik
 * 
 */
public class Main

{ 
	 static FastReader sc=new FastReader(); 
	 static int dp[][];
	 static int mod=1000000007;
	 static int max=0;
	 //static StringBuffer sb=new StringBuffer("");
	  public static void main(String[] args)
{
		   PrintWriter out=new PrintWriter(System.out);
		   //StringBuffer sb=new StringBuffer("");
		  int ttt=1;
		    //ttt =i();
	        
	        outer :while (ttt-- > 0) 
			{
	        	int n=i(),k=i(),s=i(),t=i();
	        	long A[]=new long[n];
	        	long B[]=new long[n];
	        	long D[]=new long[n];
	        	for(int i=0;i<n;i++) {
	        		A[i]=i();
	        		B[i]=i();
	        		D[i]=B[i];
	        	}
	        	long C[]=new long[k+2];
	        	C[k+1]=s;
	        	for(int i=1;i<=k;i++)
	        		C[i]=i();
	        	sort(C);
	        	sort(D);
	        	long max=0;
	        	k+=2;
	        	for(int i=1;i<k;i++) {
	        		long d=C[i]-C[i-1];
	        		max=Math.max(d, max);
	        	}
	        	int l=0;
	        	int u=n-1;
	        	long ans=-1;
	        	while(l<=u) {
	        		int mid=(l+u)/2;
	        		long y=D[mid];
	        		if(y<max) {
	        			l=mid+1;
	        			continue;
	        		}
	        		long time=0;
	        		for(int i=1;i<k;i++) {
	        			long d=C[i]-C[i-1];
	        			long x=y-d;
	        			x=Math.min(x, d);
	        			long yy=d-x;
	        			time+=(x+yy*2);
	        		}
	        		if(time<=t) {
	        			ans=y;
	        			u=mid-1;
	        		}
	        		else
	        			l=mid+1;
	        	}
	        	if(ans==-1) {
	        		System.out.println("-1");
	        		return;
	        	}
	        	long min=Integer.MAX_VALUE;
	        	for(int i=0;i<n;i++) {
	        		if(B[i]>=ans) {
	        			min=Math.min(min, A[i]);
	        		}
	        	}
	        	System.out.println(min);
	        	
	        		        	
	        	
	        }
	        	
		
		  
		  

	     //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
       	//CHECK FOR N=1
       	//CHECK FOR N=1
		        
		     
    }
			
	  




static class Pair implements Comparable<Pair>
     {
    	 int x;
    	 int y;
    	 Pair(int x,int y){
    		 this.x=x;
    		 this.y=y;
    		 
    	 }
		@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;
			}
		}
		
		/* 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;
// 		}
		public int hashCode() 
		{ 
			final int temp = 14; 
			int ans = 1; 
			ans =x*31+y*13; 
			return ans; 
		} 
  
		// Equal objects must produce the same 
		// hash code as long as they are equal 
	@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; 
	} 
	
		
     }

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 find(int A[],int a) {
	  if(A[a]==a)
		  return a;
	  return A[a]=find(A, A[a]);
}
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 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 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 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; 
        } 
    } 
} 



