#include <stdio.h>

int main(void) {
	// your code goes here
	int x,a,b,c,sum;
	scanf("%d\n",&x);
	c=x/100;
	b=(x-c*100)/10;
	a=x%10;
	sum=a+b+c;
	printf("sum=%d\n",sum);
	return 0;
}