#include<bits/stdc++.h>
using namespace std;
int main(){
    int n;
    cin>>n;
    int g=n/1%10;
    int s=n/10%10;
    int b=n/100%10;
    cout<<g+b;
	 
	return 0;
}

/**************************************************************
	Problem: 1614
	User: duyahan
	Language: C++
	Result: Accepted
	Time:10 ms
	Memory:2072 kb
****************************************************************/