#include <bits/stdc++.h>
#define rep(i, a, n) for(ll i = a; i < (n); i++)
using namespace std;
using ll = long long;
using P = pair<int, int>;
const int INF = 1001001001;
const ll LINF = 1001002003004005006ll;
//const int mod = 1000000007;
//const int mod = 998244353;

int main()
{
  ll h, w, a, b, c, d;
  cin >> h >> w >> a >> b >> c >> d;
  ll ans = LINF;
  rep(i, 0, 1000005) {
    ll ub = 10000005, lb = -1;
    while (ub - lb > 1) {
      ll mid = (ub + lb)>>1;
      if (i*c + mid*d + min((ll)i*a, h)*min(mid*b, w) >= h*w) ub = mid;
      else lb = mid;
    }
    ans = min(ans, i + ub);
  }
  cout << ans << endl;
  return 0;
}