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: def power(n,y,m=1000000007):
     n %= m
     res = 1
     while(y > 0):
        if(y & 1):
           res = res * n % m
        n = n * n % m
        y >>= 1
     
     return res
  t = int(input())
  for tc in range(t):
     n,k = map(int,input().split())
     s = bin(k)
     s = s[2:]
     a = 32-len(s)
     s='0'*(a)+s
     ans = 0
     s = s[::-1]
     for i in range(32):
        if(s[i]=='1'):
           ans=(ans+power(n, i))%1000000007
     print(ans)