#include <bits/stdc++.h>

using namespace std;

int main() {
    int d, a, b;
    cin >> d >> a >> b;

    int x = 0;
    if (a-b < 0) {
        x = d;
    } else {
        x = b*d;
    }

    cout << (a-b)*x+b*d << endl;

    return 0;
}