#include <stdio.h>
#include <string.h>

void main(void){
	char num[100] = "a";
	int input = scanf("%s",num);
	if(input == 2){
		printf("入力ミス\n");
	}
	if(strcmp(num,"0") != 0){
		printf("%s",num);
	}
	printf("0\n");
}