#include <bits/stdc++.h>

using namespace std;
typedef long long ll;

int main() {
  string s;
  cin >> s;
  int n = s.size();

  int ans = 0;
  for (int i = 0; i < n; ++i) {
    int cur = s[i] - '0';
    ans += cur == 0? 10: cur;
  }
  cout << ans << '\n';
  return 0;
}