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.io.*;
  import java.util.*;
  
  public class B {
      static long mode = (long) 1e9 + 7;
  
      public static void main(String[] args) {
          Scanner in = new Scanner(System.in);
          PrintWriter pw = new PrintWriter(System.out);
  
          int t = in.nextInt();
          for (int tt = 0; tt < t; tt++) {
              long n = in.nextLong();
              long k = in.nextLong();
  
              pw.println(solve(n, k));
          }
          pw.close();
      }
  
      static long solve(long n, long k) {
          char[] binary = Long.toBinaryString(k).toCharArray();
          long ans = 0;
          for (int i = binary.length - 1, p = 0; i >= 0; i--, p++) {
              ans += pow(p, n) * (binary[i] - '0');
              ans %= mode;
          }
          return ans;
      }
  
      static long pow(long p, long b) {
          long res = 1;
          for (int i = 0; i < p; i++) {
              res *= b;
              res %= mode;
          }
          return res;
      }
  
      static void debug(Object... obj) {
          System.err.println(Arrays.deepToString(obj));
      }
  }