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.util.*;
  public class Solution{
      
  
  static long MOD= (long)(Math.pow(10,9))+7;
  	static long Power(long a, long b)
  	{
  	    long res = 1;
  	    while (b!=0)
  	    {
  	        if ((b & 1)==1)
  	        {
  	            res = (res * a) % MOD;
  	        }
  	        a = (a * a) % MOD;
  	        b = b >> 1;
  	    }
  	    return res % MOD;
  	}
  	static long nthMagicNo(int n,int k)
  	  {
  		 int t = 1;
  	        int power = 0;
  	        for (int i = 0; i < 31; i++)
  	        {
  	            if (t >= k)
  	            {
  	                break;
  	            }
  	            t *= 2;
  	            power++;
  	        }
  	        int times = power;
  	        long ans = 0;
  	        while (k != 0)
  	        {
  	            if (k - t >= 0)
  	            {
  	                ans = (ans % MOD + Power(n, times)) % MOD;
  	                k -= t;
  	            }
  	            times--;
  	            t /= 2;
  	        }
  	      return ans;
  	    
  	  }
  	  
  	  // Driver program to test
  	  // above function
  	  public static void main(String[] args)
  	  {
  		  long modulo= (int)(Math.pow(10, 9))+7;
  		  Scanner s= new Scanner(System.in);
  		  int t = s.nextInt();
  while(t-->0) {
  	int n=s.nextInt();
  int k=s.nextInt();
  	    System.out.println( nthMagicNo(n,k)%modulo);
  	  }
  	  }
  	}
  
         
      
  
  