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 Sant {
  
  	public static void main(String[] args) {
  		// TODO Auto-generated method stub
      Scanner sc=new Scanner(System.in);
      int t=sc.nextInt();
      while(t--!=0) {
      	long n=sc.nextLong();
      	long k=sc.nextLong();
      	long ans=0,count=0;
      	int f=1000000007;
      	while(k!=0) {
      		long s=k&1;
      		if(s==1) {
      			ans=((ans%f)+(compute(n,count)%f))%f;
      		}
      		count++;
      		k>>=1;
      	}
      	System.out.println(ans);
      	
      }
      
  	}
  	static long compute(long n,long p) {
  		int k=1000000007;
  		long ans=1;
  		while(p--!=0) {
  			ans=((ans%k)*(n%k))%k;
  		}
  		return ans%k;
  	}    
  	
  
  
  }
  