#include<bits/stdc++.h>
using namespace std;
int main(){
    int n,g,s,b;
    cin>>n;
    g=n%10;
    s=n/10%10;
    b=n/100;
    cout<<g+s+b;  
}
/**************************************************************
	Problem: 1072
	User: xiaoming
	Language: C
	Result: Compile Error
****************************************************************/