#include <iostream>
using namespace std;

int main()
{
    int d, a, b;
    cin >> d >> a >> b;
    int minv = INT32_MAX;
    for (int i = 0; i <= d; i++)
    {
        minv = min(minv, i * a + (d - i) * b);
    }
    cout << minv << endl;
}