#include <bits/stdc++.h>
using namespace std;
const int N = 3e6 + 5;
long long int V[N];
long long int A, B, n;
long long int check(long long int r, long long int l, long long int t,
                    long long int m) {
  long long int mx = (A + (r - 1LL) * B);
  long long int s = V[r] - V[l - 1];
  return (s <= (m * t) and mx <= t);
}
long long int Q(long long int l, long long int t, long long int m) {
  long long int lo = l, hi = N, ans = -1;
  while (lo <= hi) {
    long long int mid = (lo + hi) >> 1;
    if (check(mid, l, t, m)) {
      ans = mid;
      lo = mid + 1;
    } else {
      hi = mid - 1;
    }
  }
  return ans;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> A >> B >> n;
  for (int i = 1; i <= 3e6; i++) {
    V[i] = A + (i - 1LL) * B;
    V[i] += V[i - 1];
  }
  for (int i = 0; i < n; i++) {
    long long int l, t, m;
    cin >> l >> t >> m;
    cout << Q(l, t, m) << '\n';
  }
  return 0;
}
