#include <algorithm>
#include <cmath>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <string>
#include <tuple>
#include <vector>

#define mkp make_pair
#define mkt make_tuple
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define all(v) v.begin(), v.end()
using namespace std;
typedef long long ll;
const ll MOD = 1e9 + 7;
// const ll MOD = 998244353;
template <class T>
void chmin(T &a, const T &b) {
    if (a > b) a = b;
}
template <class T>
void chmax(T &a, const T &b) {
    if (a < b) a = b;
}

const int LIM = 2e7;

void solve() {
    int T;
    cin >> T;
    ll X, A, Y, B;
    cin >> X >> A;
    cin >> Y >> B;

    if (T >= 0) {
        ll ans = T;
        for (ll a = 0; a < LIM; a++) {
            ll rest = T - A * a;
            ll b = 0;
            if (rest < 0) {
                b = (abs(rest) + B - 1) / B;
                rest += B * b;
            }
            chmin(ans, X * a + Y * b + rest);
        }
        cout << ans << endl;
    } else {
        ll ans = 1e18;
        for (ll b = 0; b < LIM; b++) {
            ll rest = T + B * b;
            if (rest < 0) continue;
            ll a = rest / A;
            rest -= A * a;
            chmin(ans, X * a + Y * b + rest);
        }
        cout << ans << endl;
    }
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    solve();

    return 0;
}