#include <stdio.h>
 int main()
 {
 	int n,a,b,c;
 	scanf ("%d",&n);
 	a=n/100;
 	n%=100;
 	b=n/10;
 	n%=10;
 	c=n;
 	printf("%d",a+b+c);
 	return 0;
 }
/**************************************************************
	Problem: 1716
	User: admin
	Language: C
	Result: Accepted
	Time:31 ms
	Memory:1144 kb
****************************************************************/