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.*;
  import java.lang.*;
  
  public class Solution {
  
      static final int MOD = (int) 1e9 + 7;
      static final int INT_POSITIVE_INFINITY = Integer.MAX_VALUE;
      static final long LONG_POSITIVE_INFINITY = Long.MAX_VALUE;
      static final int INT_NEGATIVE_INFINITY = Integer.MIN_VALUE;
      static final long LONG_NEGATIVE_INFINITY = Long.MIN_VALUE;
      static StringBuilder result = new StringBuilder();
  
      static class Pair {
          int a;
          int b;
  
          public Pair(int a, int b) {
              this.a = a;
              this.b = b;
          }
      }
  
      public static void main(String args[]) throws IOException {
          FastReader fr = new FastReader();
  
          int tc = fr.nextInt();
          while (tc-- > 0) {
              int n = fr.nextInt();
              int k = fr.nextInt();
              long res = 0;
              
              for (int i = 0; i < 32; i++) {
                  if ((k & (1 << i)) != 0) {
                      res = (res + fastPow(n, i)) % MOD;
                  }
              }
  
              result.append(res + "\n");
          }
  
          System.out.print(result);
      }
  
      static class FastReader {
          InputStreamReader ir;
          BufferedReader br;
          StringTokenizer st;
  
          public FastReader() {
              ir = new InputStreamReader(System.in);
              br = new BufferedReader(ir);
          }
  
          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;
          }
      }
  
      static long fastPow(long b, long e) {
          long curr = b;
          long res = 1;
  
          while (e != 0) {
              if ((e & 1) != 0) {
                  res = (res * curr) % MOD;
              }
              curr = (curr * curr) % MOD;
              e >>= 1;
          }
  
          return res;
      }
  
      static int gcd(int a, int b) {
          if (b > a) {
              return gcd(b, a);
          }
  
          if (b == 0) {
              return a;
          }
  
          return gcd(b, a % b);
      }
  
  }