#include <bits/stdc++.h>

using namespace std;

#define rep(i, a, b) for (int i = a; i < (b); ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int) (x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;

void solve() {
    ll n, a, b; cin >> n >> a >> b;
    ll ans = 0LL;
    if (a * 5 <= b) {
        ans += a * (n - n % 5);
    } else {
        ans += b * ((n - n % 5) / 5);
    }
    if (a * (n % 5) <= b) {
        ans += a * (n % 5);
    } else {
        ans += b;
    }
    cout << ans << "\n";
}

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

    solve();

    return 0;
}