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

#define INF 1234567890
#define ll long long

ll N, M, LA, LB, KA, KB;

int main()
{
	ios::sync_with_stdio(0); cin.tie(0);
	cin.exceptions(ios::badbit | ios::failbit);
	cin >> N >> M >> LA >> LB >> KA >> KB;
	ll res = INF;
	for(ll i=0; i<=N+M; i++)
	{
		ll row = min(N, i*LA);

		ll lo = 0, hi = N+M; // lo : can't, hi : can
		for(int k=0; k<25; k++)
		{
			ll mid = lo+hi>>1;

			// can i+j ?
			ll j = mid;
			ll col = min(M, j*LB);
			ll del = row*col + KA*i + KB*j;

			if (del >= N*M) hi = mid;
			else lo = mid;
		}
		ll j = hi;
		ll col = min(M, j*LB);
		ll del = row*col + KA*i + KB*j;
		if (del >= N*M) res = min(res, i+j);
	}

	cout << res << "\n";
	return 0;
}