#include <bits/stdc++.h>
using namepace std;
int main (){
    int a,b,c,d,e;
    cin>>e;
    b=a%10;
    c=a/10%10;
    d=a/100;
    e=b+c+d;
    cout<<e;
}
/**************************************************************
	Problem: 1027
	User: lijinkai
	Language: C++
	Result: Compile Error
****************************************************************/