#include <stdio.h>
int main()
{
  int ans = 0;
  char s[10003];
  scanf("%s", &s);
  int i = 0;
  while (s[i] != '\0')
  {
    if ('0' <= s[i] && s[i] <= '9')
      ans += s[i] - '0';
    i++;
  }
  printf("%d\n", ans);
  return 0;
}