#include<bits/stdc++.h>
using namespace std;
int main(){
	int x,s,g,sh,b;
	cin>>x;
	g=x%10;
	sh=x/10%10;
	b=x/100;
	s=g+sh+b;
	cout<<s;
    
}
/**************************************************************
	Problem: 1027
	User: wangyiyang
	Language: C
	Result: Compile Error
****************************************************************/