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.io.PrintWriter;
  import java.util.*;
  
  public class Solution extends Thread {
      static class FastReader {
          BufferedReader br;
          StringTokenizer st;
  
          public FastReader() {
              br = new BufferedReader(new
                                              InputStreamReader(System.in));
          }
  
          String next() {
              while (st == null || !st.hasMoreElements()) {
                  try {
                      st = new StringTokenizer(br.readLine());
                  } catch (IOException e) {
                      e.printStackTrace();
                  }
              }
              return st.nextToken();
          }
  
          int nextInt() {
              return Integer.parseInt(next());
          }
  
          long nextLong() {
              return Long.parseLong(next());
          }
  
          double nextDouble() {
              return Double.parseDouble(next());
          }
  
          String nextLine() {
              String str = "";
              try {
                  str = br.readLine();
              } catch (IOException e) {
                  e.printStackTrace();
              }
              return str;
          }
      }
  
      private static final FastReader scanner = new FastReader();
      private static final PrintWriter out = new PrintWriter(System.out);
  
      public static void main(String[] args) {
          new Thread(null, new Solution(), "Main", 1 << 28).start();
      }
  
      public void run() {
          int t = scanner.nextInt();
          for (int i = 0; i < t; i++) {
              solve();
          }
          out.close();
      }
  
      static final long MODULO = 1_000_000_007;
  
      private static void solve() {
          int n = scanner.nextInt();
          int k = scanner.nextInt();
  
          long[] powers = new long[31];
          powers[0] = 1;
          for (int i = 1; i < 31; i++) {
              powers[i] = powers[i-1] * n;
              powers[i] %= MODULO;
          }
  
          long answer = 0;
          for (int b = 0; b < 31; b++) {
              if ((k & (1 << b)) != 0) {
                  answer += powers[b];
                  answer %= MODULO;
              }
          }
          out.println(answer);
      }
  }