#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
ll n;
int a, b, c, d;
cin >> n >> a >> b >> c >> d;
ll ans = 1e18;
auto calculate1 = [&](int x) -> ll {
ll c1 = (x + a - 1) / a;
ll c2 = max(0ll, n - c1 * a + c - 1) / c;
return c1 * b + c2 * d;
};
auto calculate2 = [&](int x) -> ll {
ll c1 = (x + c - 1) / c;
ll c2 = max(0ll, n - c1 * c + a - 1) / a;
return c1 * d + c2 * b;
};
auto calculate3 = [&](int x) -> ll {
ll c1 = x / a;
ll c2 = max(0ll, n - c1 * a + c - 1) / c;
return c1 * b + c2 * d;
};
auto calculate4 = [&](int x) -> ll {
ll c1 = x / c;
ll c2 = max(0ll, n - c1 * c + a - 1) / a;
return c1 * d + c2 * b;
};
for(int i = 0; i <= min(ll(1e7), n); i++) {
ans = min(ans, calculate1(i));
ans = min(ans, calculate2(i));
ans = min(ans, calculate3(i));
ans = min(ans, calculate4(i));
}
cout << ans;
return 0;
}
