#include <iostream>
using namespace std;

int main() {
    long long H, W, La, Lb, Ka, Kb;
    cin >> H >> W >> La >> Lb >> Ka >> Kb;
    long long ret = H + W;

    for (long long A = 0; A <= H; ++A) {
        long long h = min(H, A * La), lo = -1, hi = ret - A;
        while (hi - lo > 1) {
            long long t = (lo + hi) / 2, w = min(W, Lb * t);
            (h * w + A * Ka + t * Kb >= H * W ? hi : lo) = t;
        }
        if (hi + A < ret) ret = hi + A;
    }
    cout << ret << endl;
}