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: #include <bits/stdc++.h>
  using namespace ::std;
  long long int MOD = 1000000007;
  long long int a[100001], b[100001];
  long long int power(long long int base, long long int exp1) {
    if (exp1 == 0) return 1;
    long long int val1 = power(base, exp1 / 2);
    long long int ans = (val1 * val1) % MOD;
    if (exp1 & 1) ans = (ans * base) % MOD;
    return ans;
  }
  long long int solveRecursively(long long int n, long long int k,
                                 long long int numBits) {
    if (k == 0) return 0;
    if (numBits == 1) {
      if (k == 1)
        return 1;
      else
        return 0;
    } else if (double(k) > (double(power(2, numBits - 1) - 1))) {
      return ((((long long int)power(n, numBits - 1)) % MOD) +
              (solveRecursively(n, k - power(2, numBits - 1), numBits - 1) %
               MOD)) %
             MOD;
    } else {
      return solveRecursively(n, k, numBits - 1) % MOD;
    }
  }
  long long int solve(long long int n, long long int k) {
    long long int interm = k;
    long long int num = 0;
    while (interm > 0) {
      num++;
      interm = interm / 2;
    }
    return solveRecursively(n, k, num);
  }
  vector<long long int> v;
  int main() {
    long long int t, n, m, m2, j, k, i, x;
    cin >> t;
    while (t--) {
      cin >> n >> k;
      cout << solve(n, k) << endl;
    }
    return 0;
  }
  