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.StringTokenizer;
  
  public class B {
      private static int mod = 1000000000 + 7;
  
      public static void main(String[] args) {
          CustomScanner fs=new CustomScanner();
          int t = fs.nextInt();
          for(int i=0; i<t; i++) {
              int n = fs.nextInt();
              int k = fs.nextInt();
  
              int j = 0; long res = 0;
              while(k != 0) {
                  if((k & 1) == 1) {
                      res += power(n, j, mod);
                      res = res%mod;
                  }
                  k >>= 1;
                  j++;
              }
              System.out.println(res);
          }
      }
  
      static long power(long x, long y, long p) {
          long res = 1; // Initialize result
          x = x % p;
  
          while (y > 0) {
              if ((y & 1) > 0) {
                  res = (res * x) % p;
              }
  
              y = y >> 1; // y = y/2
              x = (x * x) % p;
          }
          return res;
      }
  
      static class CustomScanner {
          BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
          StringTokenizer st=new StringTokenizer("");
          String next() {
              while (!st.hasMoreTokens())
                  try {
                      st=new StringTokenizer(br.readLine());
                  } catch (IOException e) {
                      e.printStackTrace();
                  }
              return st.nextToken();
          }
  
          int nextInt() {
              return Integer.parseInt(next());
          }
          int[] readArray(int n) {
              int[] a=new int[n];
              for (int i=0; i<n; i++) a[i]=nextInt();
              return a;
          }
          long nextLong() {
              return Long.parseLong(next());
          }
      }
  }
  