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: 
  // Working program with FastReader
  import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.util.Arrays;
  import java.util.Scanner;
  import java.util.StringTokenizer;
  import java.util.*;
  public class cf {
      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;
              }
      }
      public static class pair{
          int price;
          int quality;
          pair(int price,int quality){
              this.price=price;
              this.quality=quality;
          }
      }
      public static void main(String args[]){
          FastReader sc = new FastReader();
          int t=sc.nextInt();
          long mod=1000000007;
          while(t>0){
              t--;
              long n=sc.nextLong();
              long k=sc.nextLong();
              long ans=0;
              long i=1;
              while(k>0){
                  long r=k%2;
                  if(r!=0){
                      ans=(ans+i)%mod;
                  }
                  i=((i%mod)*(n%mod))%mod;
                  k=k/2;
              }
              System.out.println(ans);
  
          }
      }
      public static int setBit(int ans){
          int count=0;
          while(ans>0){
              if(ans%2==1)
              count++;
              ans/=2;
          }
          return count;
      }
      public static int BS(int a[],int tar){
          int low=0;
          int high=a.length-1;
          int ans=-1;
          while(low<=high){
              int mid=low+(high-low)/2;
              if(a[mid]==tar){
                  return mid;
              }
              else if(a[mid]>tar){
                  high=mid-1;
              }
              else{
                  low=mid+1;
              }
          }
          return ans;
      }
      public static int UpperBound(int a[],int tar){
          int low=0;
          int high=a.length-1;
          int ans=-1;
          while(low<=high){
              int mid=low+(high-low)/2;
              if(a[mid]<=tar){
                  ans=mid;
                  low=mid+1;
              }
              else{
                  high=mid-1;
              }
          }
          return ans;
      }
  }
  