#include <bits/stdc++.h>

using namespace std;

template <typename T> T gcd(T x, T y) {
  if (y == 0)
    return x;
  return gcd(y, x % y);
}

template <typename T> T lcm(T x, T y) {
  if (x == 0 || y == 0)
    return 0;
  return x / gcd(x, y) * y;
}

int main() {
  char S;
  int ans = 0;
  while (cin >> S) {
    if (S == '0')
      ans += 10;
    else
      ans += S - '0';
  }
  cout << ans << endl;
}