#include <bits/stdc++.h>

#define rep(i, n, s) for(int (i) = 0; (i) < (n); (i) += (s))

using namespace std;

int main()
{
  string str; 
  cin >> str;

  int result = 0;

  for (int i = 0; i < str.length(); ++i)
  {
    if('0' <= str[i] && str[i] <= '9')
    {
      result += str[i] - '0';
    }
  }

  cout << result << endl;
}