#include <bits/stdc++.h>   using namespace std;   long long A, B, N;   long long L, T, M;   bool ok(long long R) {     long long mx = A + (R - 1) * B;     long long mn = A + (L - 1) * B;     long long D = R - L;     if (mx > T) return false;     return (mn * (D + 1) + B * D * (D + 1) / 2) <= T * M;   }   int main(void) {     cin >> A >> B >> N;     while (N--) {       cin >> L >> T >> M;       long long R = L;       long long mn = A + (L - 1) * B;       if (mn > T) {         R = -1;       } else {         long long XR = 1LL << 22;         while (XR > R) {           long long m = (R + XR) / 2;           if (!ok(m))             XR = m;           else             R = m + 1;         }         R -= 1;       }       cout << R <<   n ;     }     return 0;   }   