#include <bits/stdc++.h>
using namespace std;
#define rep(i,l,r) for(int i=(l);i<(r);++i)
typedef long long ll;

int main(){
	int d,a,b; cin>>d>>a>>b;
	int mn=100000001;
	rep(i,0,d+1){
		mn=min(mn,i*a+(d-i)*b);
	}
	cout<<mn<<endl;
}