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.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.util.StringJoiner;
  
  public class B {
      static long magic(long n, long k){
          long pow = 0;
          long factor = 1_000_000_007;
          if(k==1){
              return 1;
          }
          long res = 0;
          if ((k & 1) == 1) {
              res+=1;
          }
  
          while (k > 0) {
              k >>= 1;
              pow++;
              if ((k & 1) == 0) {
                  continue;
              }
              long resTmp = n%factor;
              for(int i=1;i<pow;i++){
                  resTmp = (resTmp*n)%factor;
              }
  
              res += resTmp;
              res %= factor;
          }
          return res;
      }
      public static void main(String[] args) throws IOException {
          BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
  
          // Reading data using readLine
          int t = new Integer(reader.readLine());
          StringJoiner sj = new StringJoiner("\r\n");
          long factor = 1_000_000_007;
          for (int i = 0; i < t; i++) {
              String[] d = reader.readLine().split("\\s+");
              long n = new Integer(d[0]);
              long k = new Integer(d[1]);
              long magic = magic(n,k);
              sj.add("" + magic);
  
          }
          System.out.println(sj.toString());
      }
  }