#include<bits/stdc++.h>
#define int long long
using namespace std;
int n,c,v,dp[1234567],ans=0x3f3f3f3f3f3f3f3f;
signed main(){
//	freopen("ctrlcv.in","r",stdin);
//	freopen("ctrlcv.out","w",stdout);
	cin>>n>>c>>v;
	n*=2;
	for(int i=2;i<=n;i++)dp[i]=0x3f3f3f3f3f3f3f3f;
	for(int i=1;i<=n;i++){
		int cnt=0;
		for(int j=2*i;j<=n;j+=i)dp[j]=min(dp[j],dp[i]+c+v*(++cnt));
	}
	for(int i=n/2;i<=n;i++)ans=min(ans,dp[i]);
	cout<<ans<<endl;
	return 0;
}