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: //package practice;
  
  import java.io.*;
  import java.util.StringTokenizer;
  
  public class B1594 {
  
  
      static final int MOD = 1000000007;
      static PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
  
      static int fasterScanner() {
          try {
              boolean in = false;
              int res = 0;
              for (; ; ) {
                  int b = System.in.read() - '0';
                  if (b >= 0) {
                      in = true;
                      res = 10 * res + b;
                  } else if (in) {
                      return res;
                  }
              }
          } catch (IOException e) {
              throw new Error(e);
          }
      }
  
      public static void main(String[] args) {
          FastScanner sc = new FastScanner();
          int t = fasterScanner();
          while (t-- > 0) {
              int n = fasterScanner();
              int k = fasterScanner();
              String bin = Integer.toBinaryString(k);
              int len = bin.length();
              int ans = 0;
              for (int i = len - 1; i >= 0; i--) {
                  ans += modulo(n, len - 1 - i, MOD) * Integer.parseInt(String.valueOf(bin.charAt(i)));
                  ans %= MOD;
              }
              out.println(ans);
          }
          out.close();
      }
  
      static int modulo(int a, int b, int c) {
          long x = 1;
          long y = a;
          while (b > 0) {
              if (b % 2 == 1) {
                  x = (x * y) % c;
              }
              y = (y * y) % c; // squaring the base
              b /= 2;
          }
          return (int) x % c;
      }
  
      static class FastScanner {
  
          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) {
                  }
              }
              return st.nextToken();
          }
  
          int nextInt() {
              return Integer.parseInt(next());
          }
  
          long nextLong() {
              return Long.parseLong(next());
          }
      }
  }
  