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



/**************************************************************
	Problem: 1605
	User: zhuangsongyu
	Language: C++
	Result: Accepted
	Time:10 ms
	Memory:2072 kb
****************************************************************/