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;
  const int MOD = 1000000007;
  long long power(long long x, long long n) {
    long long res = 1;
    while (n) {
      if (n & 1) {
        res = (res * x);
      }
      n >>= 1;
      if (n != 0) {
        x = (x * x);
      }
    }
    return res;
  }
  long long powerMOD(long long x, long long n) {
    long long res = 1;
    while (n) {
      if (n & 1) {
        res = (res * x) % MOD;
      }
      n >>= 1;
      x = (x * x) % MOD;
    }
    return res;
  }
  bool mycompare(pair<long long, long long> &a, pair<long long, long long> &b) {
    if (a.first == b.first) {
      return a.second < b.second;
    }
    return a.first > b.first;
  }
  bool mycompare1(pair<int, int> &a, pair<int, int> &b) {
    return a.second < b.second;
  }
  void solve() {
    long long i, j, k, n, m, l, x;
    cin >> n >> k;
    x = 0;
    l = 0;
    while (k) {
      if (k & 1) x += powerMOD(n, l);
      x %= MOD;
      k >>= 1;
      l++;
    }
    cout << x << "\n";
  }
  int main() {
    ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
    srand(time(NULL));
    ;
    int t = 1, i;
    cin >> t;
    for (int i = 0; i < t; i++) solve();
    return 0;
  }
  