func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     ios_base::sync_with_stdio(false);     cin.tie(0);     cout.tie(0);     int t;     cin >> t;     while (t--) {       int n, x;       cin >> n >> x;       vector<pair<int, int> > v;       for (int i = 0; i < n; i++) {         int k, l;         cin >> k >> l;         v.push_back(make_pair(k, l));       }       int j = 0, ma = -1, b = 0;       for (int i = 0; i < n; i++) {         b = max(b, v[i].first);         if ((v[i].first - v[i].second) > ma) {           ma = max(v[i].first - v[i].second, ma);           j = v[i].first;         } else if ((v[i].first - v[i].second) == ma) {           if (v[i].first > j) {             j = v[i].first;           }         }       }       if (b >= x) {         cout <<  1  << endl;       } else if (ma > 0) {         if ((x - b) % ma == 0) {           cout << (x - b) / ma + 1 << endl;         } else {           cout << (x - b) / ma + 2 << endl;         }       } else {         cout <<  -1  << endl;       }     }     return 0;   }   