#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main () {
    ll H, W, La, Lb, Ka, Kb;
    cin >> H >> W >> La >> Lb >> Ka >> Kb;
    ll ans = H + W + 5000;
    ll inf = 1e9 + 7;
    for (ll a = 0; a <= ans; a ++) {
        ll p1 = min(H, a * La);
        ll p2 = Kb;
        ll q = Ka * a;
        ll ok = (p2 ? (H * W) / p2 + 1 : inf), ng = -1;
        while (abs(ok - ng) > 1) {
            ll mu = (ok + ng) / 2;
            if (p1 * min(mu * Lb, W) + q + p2 * mu >= H * W) {
                ok = mu;
            } else {
                ng = mu;
            }
        }
        ans = min(ans, ok + a);
    }
    cout << ans << endl;
}