// 

#include <bits/stdc++.h>
using namespace std;

using ll = long long;

#define rep(i, n) for (int i=0; i<(int)(n); ++(i))
#define rep3(i, m, n) for (int i=(m); (i)<(int)(n); ++(i))
#define repr(i, n) for (int i=(int)(n)-1; (i)>=0; --(i))
#define rep3r(i, m, n) for (int i=(int)(n)-1; (i)>=(int)(m); --(i))
#define all(x) (x).begin(), (x).end()

const int INF = (int)(1e9);

int main() {
    int h, w, la, lb;
    ll ka, kb;
    cin >> h >> w >> la >> lb >> ka >> kb;
    int amx = (h+la-1) / la, bmx = (w+lb-1) / lb, res = INF;
    repr(acnt, amx+1) {
        int alen = min(h, acnt*la);
        ll adda = acnt * ka;
        rep(bcnt, bmx+1) {
            if (acnt+bcnt >= res) break;
            int blen = min(w, bcnt*lb);
            ll addb = bcnt * kb;
            if ((ll)alen*blen+adda+addb >= (ll)h*w) {
                res = min(res, acnt+bcnt);
                break;
            }
        }
    }
    cout << res << endl;
    return 0;
}