#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); i++)
using namespace std;
typedef long long ll;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    ll T,X,A,Y,B; cin >> T >> X >> A >> Y >> B;
    if(T < 0) {
        swap(X, Y);
        swap(A, B);
    }
    ll ans = numeric_limits<ll>::max();
    for(ll x = 0; x <= ll(1e7); x++) {
        ll y = (A * x - T + B - 1) / B;
        ll z = T - (A * x - B * y);
        if(0 <= y && 0 <= z)
            ans = min(ans, X * x + Y * y + z);
        y = (A * x - T) / B;
        z = T - (A * x - B * y);
        if(0 <= y && 0 <= z)
            ans = min(ans, X * x + Y * y + z);
    }
    cout << ans << endl;
}