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

int main()
{
	string S;
	cin >> S;

	int ans = 0;
	for( int i = 0; i < S.size(); i++ ) {
		if( S[i] == '0' ) ans += 10;
		else ans += S[i] - '0';
	}

	cout << ans << endl;
}