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 sys
  
  if __name__ == "__main__":
      inp = sys.stdin.readline()
      test = int(inp.strip('\n'))
  
      result = ""
      for i in range(test):
          inp = sys.stdin.readline()
          n, k = list(map(int, inp.strip('\n').split()))
  
          val = bin(k).lstrip('0b')
          size = len(val)
  
          num = 0
  
          for i in range(size):
              if val[i] == '1':
                  num = num + n ** (size - 1 - i)
          num %= 1000000000 + 7
          sys.stdout.write(str(num) + '\n')
  