#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
#define pb push_back
#define mp make_pair
#define rep(i,n) for(int i=0;i<(n);++i)

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	string s;cin >> s;
	int ans=0;
	rep(i,s.size()){
		if(s.at(i)=='0') ans+=10;
		else ans+=s.at(i)-'0';
	}
	cout << ans << endl;
}