#include <bits/stdc++.h>
using namespace std;

int main() {
    int d, a, b; 
    cin >> d >> a >> b;
    int ans = 1 << 30;
    for(int x=0;x<=d;x++) {
        ans = min(ans, x * a + (d - x) * b);
    }
    cout << ans << endl;
}