#include <bits/stdc++.h>

using namespace std;

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

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

  cout << ret << endl;
}