#include <bits/stdc++.h>
using namespace std;

int main() {
  string S;
  cin >> S;
  int ans = 0;
  for (int i = 0; i < S.size(); i++)
    if (S[i] >= '0' && S[i] <= '9')
      ans += S[i] - '0';
  cout << ans << endl;
}