#include <iostream>

using namespace std;

int main() {
  string s;
  cin >> s;
  int sum = 0;
  for (char& c : s) {
    if (c < '0' || c > '9') {
      continue;
    }
    sum += (int)(c - '0');
  }
  cout << sum << endl;
  
  return 0;
}