#include <bits/stdc++.h>
using namespace std;
typedef unsigned long long ul;
typedef signed long long ll;
ul over = 1000000007;

int main(void)
{
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed;
  string s;
  cin >> s;
  ll ans = 0;
  for (auto c : s) {
    if ('0' <= c && c <= '9') ans += c-'0';
  }
  cout << ans << endl;
  return 0;
}