#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define ull unsigned long long
#define db double
#define pii pair<int,int>
#define pll pair<ll,ll>
#define ti3 tuple<int,int,int>
#define int128 __int128_t
#define pii128 pair<int128,int128>
const int inf = 1 << 30;
const ll linf = 1e18;
const ll mod = 1e9 + 7;
const db EPS = 1e-10;
const db pi = acos(-1);
template<class T> bool chmin(T& x, T y){
    if(x > y) {
        x = y;
        return true;
    } else return false;
}
template<class T> bool chmax(T& x, T y){
    if(x < y) {
        x = y;
        return true;
    } else return false;
}

// overload macro
#define CAT( A, B ) A ## B
#define SELECT( NAME, NUM ) CAT( NAME, NUM )

#define GET_COUNT( _1, _2, _3, _4, _5, _6 /* ad nauseam */, COUNT, ... ) COUNT
#define VA_SIZE( ... ) GET_COUNT( __VA_ARGS__, 6, 5, 4, 3, 2, 1 )

#define VA_SELECT( NAME, ... ) SELECT( NAME, VA_SIZE(__VA_ARGS__) )(__VA_ARGS__)

// rep(overload)
#define rep( ... ) VA_SELECT(rep, __VA_ARGS__)
#define rep2(i, n) for (decay_t<decltype(n)> i = 0; i < n; i++)
#define rep3(i, a, b) for (decay_t<decltype(a)> i = a; i < b; i++)
#define rep4(i, a, b, c) for (decay_t<decltype(a)> i = a; i < b; i += c)

// rrep(overload)
#define rrep( ... ) VA_SELECT(rrep, __VA_ARGS__)
#define rrep2(i, n) for (decay_t<decltype(n)> i = n - 1; i >= 0; i--)
#define rrep3(i, a, b) for (decay_t<decltype(a)> i = b - 1; i >= a; i--)
#define rrep4(i, a, b, c) for (decay_t<decltype(a)> i = b - 1; i >= a; i -= c)

// for_earh
#define fore(e, v) for (auto&& e : v)

// vector
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()

int main() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    cout << fixed << setprecision(20);
    ll H, W, LA, LB, KA, KB;
    cin >> H >> W >> LA >> LB >> KA >> KB;
    ll ans = linf;
    rep (i, H + W + 1) {
        ll h = min(H, i * LA);
        ll lb = -1, ub = inf;
        while (ub - lb > 1) {
            ll mid = (ub + lb) / 2;
            ll w = min(W, mid * LB);
            if (w * h + i * KA + mid * KB >= H * W) ub = mid;
            else lb = mid;
        }
        chmin(ans, ub + i);
    }
    cout << ans << "\n";
}