description: Theofanis really likes sequences of positive integers, thus his teacher (Yeltsa Kcir) gave him a problem about a sequence that consists of only special numbers.
  
  Let's call a positive number special if it can be written as a sum of different non-negative powers of n. For example, for n = 4 number 17 is special, because it can be written as 4^0 + 4^2 = 1 + 16 = 17, but 9 is not.
  
  Theofanis asks you to help him find the k-th special number if they are sorted in increasing order. Since this number may be too large, output it modulo 10^9+7.
  
  Input
  
  The first line contains a single integer t (1 ≤ t ≤ 10^4) — the number of test cases.
  
  The first and only line of each test case contains two integers n and k (2 ≤ n ≤ 10^9; 1 ≤ k ≤ 10^9).
  
  Output
  
  For each test case, print one integer — the k-th special number in increasing order modulo 10^9+7.
  
  Example
  
  Input
  
  
  3
  3 4
  2 12
  105 564
  
  
  Output
  
  
  9
  12
  3595374
  
  Note
  
  For n = 3 the sequence is [1,3,4,9...]
solution:  import java.util.*;
   import java.lang.*;
   import java.io.*;
  
  public class B_Special_Numbers
   {
       static int M = 1_000_000_007;
       static final PrintWriter out =new PrintWriter(System.out);
       static final FastReader fs = new FastReader();
       static boolean prime[];
       public static void main (String[] args) throws java.lang.Exception
       {
             
             int t= fs.nextInt();
             for(int i=0;i<t;i++)
             {
                 long n=fs.nextLong();
                 long k=fs.nextLong();
                 long kk=k;
                 long ans=0;
                 while(kk>0){
                  long temp = kk;
      long power = (long) ((double)Math.log(temp) /(double) Math.log(2));
    //  out.println(power);
      long result = (long) power(n, power);
     // out.println(result);
      ans=(ans%M+result%M)%M;
      kk=kk-(long)power(2,power);
     // out.println(kk);
                 }
                 out.println(ans%M);
             }
             out.flush();
    }
    public static long power(long x, long y)
      {
          long temp;
          if (y == 0)
              return 1;
          temp = power(x, y / 2);
    
          if (y % 2 == 0)
              return modMult(temp,temp);
          else {
              if (y > 0)
                  return modMult(x,modMult(temp,temp));
              else
                  return (modMult(temp,temp)) / x;
          }
      }
    static void sieveOfEratosthenes(int n)
      {
           prime = new boolean[n + 1];
          for (int i = 0; i <= n; i++)
              prime[i] = true;
              prime[0]=false;
              if(1<=n)
              prime[1]=false;
          for (int p = 2; p * p <= n; p++)
          {
              
              if (prime[p] == true)
              {
                 
                  for (int i = p * p; i <= n; i += p)
                      prime[i] = false;
              }
          }
      }
           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;
           }
   int [] arrayIn(int n) throws IOException
       {
           int  arr[] = new int[n];
           for(int i=0; i<n; i++)
           {
               arr[i] = nextInt();
           }
           return arr;
       }
       }
       
       public static class Pairs implements Comparable<Pairs>
       {
           int value,index;
           Pairs(int value, int index)
           {
               this.value = value;
               this.index = index;
           }
           public int compareTo(Pairs p)
           {
               return Integer.compare(this.value, p.value);
           }
       }
       static final Random random = new Random();
    
       static void ruffleSort(int arr[])
       {
           int n = arr.length;
           for(int i=0; i<n; i++)
           {
               int j = random.nextInt(n),temp = arr[j];
               arr[j] = arr[i];
               arr[i] = temp;
           }
           Arrays.sort(arr);
       }
       static long nCk(int n, int k) {
           return (modMult(fact(n),fastexp(modMult(fact(n-k),fact(k)),M-2)));
       }
    
       static long fact (long n) {
    
           long fact =1;
           for(int i=1; i<=n; i++) {
               fact = modMult(fact,i);
           }
           return fact%M;
       }
    
       static long modMult(long a,long b) {
           return a*b%M;
       }
    
       static long fastexp(long x, int y){
           if(y==1) return x;
    
           long ans = fastexp(x,y/2);
           if(y%2 == 0) return modMult(ans,ans);
           else return modMult(ans,modMult(ans,x));
       }
   }