#include<bits/stdc++.h>
using namespace std;
int n,c,v,ans=0x3f3f3f3f,dp[100005];
int main()
{
	freopen("ctrlcv.in","r",stdin);
	freopen("ctrlcv.out","w",stdout);
	cin>>n>>c>>v;n<<=1;
	memset(dp,0x3f,sizeof(dp));dp[1]=0;
	for(int i=1;i<=n;i++)for(int j=2;j<=n/i;j++)dp[i*j]=min(dp[i*j],dp[i]+c+v*(j-1));
	for(int i=n/2;i<=n;i++)ans=min(ans,dp[i]);
	cout<<ans;
}