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

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

	int ans = INT32_MAX / 2;
	for( int x = 0; x <= d; x++ ) {
		ans = min( ans, x * a + ( d - x ) * b );
	}

	cout << ans << endl;
}