#include <bits/stdc++.h>

using namespace std;

struct Initializer {
  Initializer() {
    cin.tie(0);
    ios::sync_with_stdio(0);
    cout << fixed << setprecision(15);
  }
} initializer;

int main() {
  string s;
  cin >> s;
  int res = 0;
  for (char c : s) {
    if (isdigit(c)) res += c - '0';
  }
  cout << res << endl;
}