#include <bits/stdc++.h>
using namespace std;
long long A, B, n;
long long L, t, m;
const long long one = 1;
const long long two = 2;
long long get_sum(long long z) {
  if (z < 1) return 0;
  long long res = (z * (z + one)) / two;
  return res;
}
void solve() {
  cin >> L >> t >> m;
  long long num = A + (L - one) * B;
  if (num > t) {
    cout << "-1" << endl;
    return;
  }
  long long LL = L;
  long long RR = 100000000;
  long long R;
  while (true) {
    if (LL == RR) {
      R = LL;
      break;
    }
    long long MM = (LL + RR) / two + one;
    long long number = A + (MM - one) * B;
    if (number <= t)
      LL = MM;
    else
      RR = MM - 1;
  }
  LL = L;
  RR = R;
  long long Max_Number = t * m;
  while (true) {
    if (LL == RR) {
      cout << LL << endl;
      return;
    }
    long long MM = (LL + RR) / two + one;
    long long number = (MM - L + one) * A;
    long long dop = get_sum(MM - one) - get_sum(L - two);
    number += (dop * B);
    if (number <= Max_Number)
      LL = MM;
    else
      RR = MM - 1;
  }
  return;
}
int main() {
  cin >> A >> B >> n;
  for (int i = 1; i <= n; i++) {
    solve();
  }
  return 0;
}
