#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
using namespace std;
int main() {
	int a, b, c, d;
	int e=0;
	cin >> d;
	cin >> a >> b;
	for (int i = 0; i <=d; i++) {
		c = i * a + (d - i) * b;
		e = c;
		e = min(e, c);
	}
	cout << e << endl;
	return 0;
}