#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,g,s,b,h;
	cin>>n;
	g=n%10;
	s=n/10%10;
	b=n/100;
	h=b+s+g;
	printf("%d",h);
}
/**************************************************************
	Problem: 1716
	User: xiaojingxuan
	Language: C++
	Result: Accepted
	Time:22 ms
	Memory:2072 kb
****************************************************************/