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

/**************************************************************
	Problem: 1027
	User: chenjunlin
	Language: C++
	Result: Accepted
	Time:10 ms
	Memory:2072 kb
****************************************************************/