#include<bits/stdc++.h>
using namespace std;

int main(){
	int n,a,b;
	cin>>n;
	a=n%10;
	b=n/10%10;
	cout<<a+b;
	return 0;
}

/**************************************************************
	Problem: 1605
	User: linzihang
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/