#include<bits/stdc++.h>
using namespace std;
int main(){
	int x,g,s,b,h=0;
	cin>>x;
	g=x%10;
	s=x/10%10;
	b=x/100;
	h=g+s+b;
	cout<<h;







	return 0;
} 
/**************************************************************
	Problem: 1027
	User: zhangchenhao
	Language: C
	Result: Compile Error
****************************************************************/