#include <iostream>
#include <vector>
#include <string>
#include <iomanip>
#include <queue>
#include <cmath>
#include <algorithm>
#include <tuple>
#include <iomanip>
#include <stdio.h>
#include <map>
#include <bitset>
#include <set>
#include <stack>
#include <queue>
#include <unordered_set>
#include <cassert>


//#pragma GCC optimize("Ofast,no-stack-protector")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC optimize("fast-math")
//#pragma GCC optimize("section-anchors")
//#pragma GCC optimize("profile-values,profile-reorder-functions,tracer")
//#pragma GCC optimize("vpt")
//#pragma GCC optimize("rename-registers")
//#pragma GCC optimize("move-loop-invariants")
//#pragma GCC optimize("unswitch-loops")
//#pragma GCC optimize("function-sections")
//#pragma GCC optimize("data-sections")
//#pragma GCC optimize("branch-target-load-optimize")
//#pragma GCC optimize("branch-target-load-optimize2")
//#pragma GCC optimize("btr-bb-exclusive")


#define int long long
#define ll long long
#define ull unsigned long long
#define all(a) a.begin(), a.end()
#define pii pair<int, int>
#define pb push_back
#define ld long double


using namespace std;

const int INF = 1e17;
//const int mod = 2600000069;
//const int p = 179;

signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int n, a, b, c, d;
    cin >> n >> a >> b >> c >> d;
    vector<int> dp(n + 1, INF);
    dp[0] = 0;
    for (int i = 1; i < n + 1; i++) {
        dp[i] = i;
        if (i >= c) {
            dp[i] = min(dp[i], dp[i - c] + d);
        } else {
            dp[i] = min(dp[i], d);
        }
        if (i >= a) {
            dp[i] = min(dp[i], dp[i - a] + b);
        } else {
            dp[i] = min(dp[i], b);
        }
    }
    cout << dp[n];
}
/*

*/