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 javax.swing.plaf.synth.SynthSplitPaneUI;
  
  public class B {
  
      static int mod=1000000007;
      public static void main(String[] args){
          Scanner s=new Scanner(System.in);
          int t=s.nextInt();
          while(t-->0){
              int n = s.nextInt();
              int k = s.nextInt();
              long prod = 1;
              long ans = 0;
              while(k != 0){
                  int o = k%2;
                  if (o == 1){
                      ans += prod;
                      ans %= mod;
                  }
                  k/=2;
                  prod *= n;
                  prod %= mod;
              }
              System.out.println(ans);
  
          }
          s.close();
      }
  }
  