#include<stdio.h>
#define inf 1145141919

int min(int x,int y){if(x > y){return y;}return x;}

int main(void){
	int n,c,v,x[131072],i,j,m,b = inf;
	scanf("%d%d%d",&n,&c,&v);
	x[1] = 0;
	for(i = 2;i <= 131071;i++){x[i] = c+v*(i-1);}
	for(i = 2;i <= 131071;i++){
		m = x[i];
		for(j = 2*i;j <= 131071;j+=i){x[j] = min(x[j],m+c+v*((j/i)-1));}		
	}
	for(i = n;i < 2*n;i++){b = min(b,x[i]);}
	printf("%d\n",b);
	return 0;
}