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 codechef; // don't place package name! */
  
  import java.util.*;
  import java.lang.*;
  import java.io.*;
  
  /* Name of the class has to be "Main" only if the class is public. */
  public class Codechef
  {
  	public static void main (String[] args) throws java.lang.Exception
  	{
  		// your code goes here
  		Scanner scn = new Scanner(System.in);
  		int t = scn.nextInt();
  		while(t>0){
  		    t--;
  		    long n = scn.nextInt();
  		    long k = scn.nextInt();
  		    System.out.println(getAns(n, k )%1000000007);
  		}
  	}
  	
  	public static long getAns(long n, long k){
  	    if(k==0){
  	        return 0;
  	    }
  	    long a = 1;
  	    long sum = 0;
  	    int count = 0;
  	    long ans = 1;
  	    while(a + sum < k){
  	        count++;
  	        sum += a;
  	        a = a*2;
  	        ans *= n;
  	        ans %= 1000000007;
  	    }
  	    k = k-sum-1;
  	    ans = ans%1000000007;
  	    return ans + getAns(n, k);
  	    
  	}
  }
  