#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000001

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