#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define eb emplace_back
#define pb push_back
#define fi first
#define se second
#define ii pair<int,int>
#define ve vector
#define all(x) x.begin(), x.end()
#define fo(i,a,b) for (int i=(a); i<=(b); ++i)
#define fd(i,a,b) for (int i=(a); i>=(b); --i)
#define maxi(a, b) a = max(a, b)
#define mini(a, b) a = min(a, b)
#define _ << ' ' <<
const int N = 2e7+5, inf = 1e9+10, mod = 1e9+7;
const ll inf64=1e18+1;
/**
**/
ll n, a, b, c, d;
inline ll calc(ll x, ll num, ll cost) {
ll tt = (x + num - 1) / num;
if (tt>=inf64/cost||cost*tt>=inf64) return inf64;
return cost*tt;
}
inline ll cal(ll x) {
return min(calc(x,a,b),calc(x,c,d));
}
void sol() {
cin >> n >> a >> b >> c >> d;
if (1ll * b * c >= 1ll * a * d) swap(a, c), swap(b, d);
ll ans = inf;
fo(i,0,min(n,(ll)1e8)) {
if (1ll * i * c > n) break;
mini(ans, 1ll * i * d + cal(n - 1ll * i * c));
}
cout<<ans;
}
signed main(){
ios::sync_with_stdio(0); cin.tie(0);
if(fopen("A.inp","r")) {
freopen("A.inp","r",stdin);
freopen("A.out","w",stdout);
}
int tc = 1; // cin >> tc;
fo(i,1,tc) sol();
return 0;
}
