using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;

class TEST{
	static void Main(){
		Sol mySol =new Sol();
		mySol.Solve();
	}
}

class Sol{
	public void Solve(){
		
		long[] dp = new long[N+1];
		long Inf = (long) 1e18;
		for(int i=0;i<=N;i++) dp[i] = Inf;
		
		dp[1] = 0;
		for(int i=1;i<N;i++){
			long cost = C;
			for(int j=i+i;j<=N;j+=i){
				cost += V;
				dp[j] = Math.Min(dp[j],dp[i]+cost);
				if(j < N && j+i > N){
					cost += V;
					dp[N] = Math.Min(dp[N],dp[i] + cost);
				}
			}
		}
		
		Console.WriteLine(dp[N]);
	}
	int N;
	long C,V;
	public Sol(){
		N = ri();
		var d = rla();
		C = d[0]; V = d[1];
	}

	static String rs(){return Console.ReadLine();}
	static int ri(){return int.Parse(Console.ReadLine());}
	static long rl(){return long.Parse(Console.ReadLine());}
	static double rd(){return double.Parse(Console.ReadLine());}
	static String[] rsa(char sep=' '){return Console.ReadLine().Split(sep);}
	static int[] ria(char sep=' '){return Array.ConvertAll(Console.ReadLine().Split(sep),e=>int.Parse(e));}
	static long[] rla(char sep=' '){return Array.ConvertAll(Console.ReadLine().Split(sep),e=>long.Parse(e));}
	static double[] rda(char sep=' '){return Array.ConvertAll(Console.ReadLine().Split(sep),e=>double.Parse(e));}
}