#include  "stdio.h"
int main() {
	int x,y;
	scanf("%d",&x);
	if(x <1) {
		y=x;
		printf("%d",y);
	} else  if(x <10) {
		y=2*x-1;
		printf("%d",y);
	} else {
		y=3*x-11;
		printf("%d",y);
	}
	return 0;
}