#include<iostream>
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: lijinkai
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2072 kb
****************************************************************/