import java.util.Arrays;
import java.util.Scanner;
import java.util.stream.IntStream;

public class Main{
	static IntStream REPS(int v){return IntStream.range(0,v);}
	static IntStream REPS(int l,int r){return IntStream.rangeClosed(l,r);}
	static IntStream INS(int n) {return REPS(n).map(i->getInt());}
	static Scanner s=new Scanner(System.in);
	static int getInt(){return Integer.parseInt(s.next());}
	public static void main(String[]$){
		int n=getInt();
		long c=getInt(),v=getInt();
		long[]dp=new long[n*2+1];
		Arrays.fill(dp,Long.MAX_VALUE);
		dp[1]=0;
		for(int i=1;i<=n*2;++i){
			for(int j=1;j*i+i<=n*2;++j) {
				dp[j*i+i]=Math.min(dp[j*i+i],dp[i]+c+v*j);
			}
		}
		System.out.println(REPS(n,n+2).mapToLong(i->dp[i]).min().getAsLong());
	}
}