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>
  #pragma GCC optimize("Ofast,unroll-loops")
  #pragma GCC target("avx,avx2,sse,sse2")
  using namespace std;
  using vi = vector<long long>;
  mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
  long long powmod(long long a, long long b, long long mod) {
    if (b == 0 || a == 1) {
      if (mod == 1)
        return 0;
      else
        return 1;
    }
    if (b % 2 == 0) {
      long long k = powmod(a, b / 2, mod);
      return (k * k) % mod;
    } else {
      long long k = powmod(a, b / 2, mod);
      return ((k * k) % mod * a) % mod;
    }
  }
  long long gcd(long long a, long long b) {
    if (a == 0) return b;
    if (b == 0) return a;
    if (a > b)
      return gcd(a % b, b);
    else
      return gcd(b % a, a);
  }
  long long prime(long long p) {
    if (p == 1) return 0;
    for (long long i = 2; i * i <= p; i++) {
      if (p % i == 0 && i < p) return i;
    }
    return 1;
  }
  long long inv(long long a, long long mod) { return powmod(a, mod - 2, mod); }
  long long random_modul() {
    uniform_int_distribution<long long> u1(1e9, 2e9);
    long long pepega = u1(rnd);
    while (prime(pepega) != 1) pepega = u1(rnd);
    return pepega;
  }
  template <typename T1>
  void ifmax(T1& max, T1 kek) {
    if (kek > max) max = kek;
    return;
  }
  template <typename T1>
  void ifmin(T1& min, T1 kek) {
    if (kek < min) min = kek;
    return;
  }
  template <typename T1>
  istream& operator>>(std::istream& in, pair<T1, T1>& a) {
    in >> a.first >> a.second;
    return in;
  }
  template <typename T1>
  istream& operator>>(std::istream& in, vector<T1>& a) {
    for (long long i = 0; i < a.size(); i++) in >> a[i];
    return in;
  }
  template <typename T1>
  ostream& operator<<(std::ostream& out, vector<T1>& b) {
    for (long long i = 0; i < b.size(); i++) out << b[i] << " ";
    out << "\n";
    return out;
  }
  template <typename T1>
  void sort(vector<T1>& m) {
    sort(m.begin(), m.end());
  }
  template <typename T1>
  void reverse(vector<T1>& m) {
    reverse(m.begin(), m.end());
  }
  long long mod = 1000000007;
  long long fac[200005];
  long long inv_fac[200005];
  long long co(long long a, long long b) {
    long long ans = 1;
    ans *= fac[b];
    ans *= inv_fac[b - a];
    ans %= mod;
    ans *= inv_fac[a];
    return ans % mod;
  }
  bool is_sorted(vector<long long> a) {
    long long check = 1;
    for (long long i = 0; i + 1 < a.size(); i++)
      if (a[i + 1] < a[i]) check = 0;
    if (check)
      return true;
    else
      return false;
  }
  void solve() {
    long long a, k;
    cin >> a >> k;
    vector<long long> lul;
    long long q = k;
    while (q) {
      lul.push_back(q % 2);
      q /= 2;
    }
    long long cur = 1;
    long long ans = 0;
    for (long long i = 0; i < lul.size(); i++) {
      ans += lul[i] * cur;
      ans %= mod;
      cur *= a;
      cur %= mod;
    }
    cout << ans << "\n";
    return;
  }
  signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cout << fixed << setprecision(10);
    long long multitest = 1;
    long long tututu;
    tututu = 1;
    long long combinatorics = 0;
    if (combinatorics) {
      fac[1] = 1;
      fac[0] = 1;
      for (long long i = 2; i < 200005; i++) {
        fac[i] = fac[i - 1] * i;
        fac[i] %= mod;
      }
      for (long long i = 0; i < 200005; i++) {
        inv_fac[i] = inv(fac[i], mod);
      }
    }
    if (multitest) cin >> tututu;
    for (long long qwerty = 0; qwerty < tututu; qwerty++) solve();
    return 0;
  }
  