#include <stdio.h>

int main(void){
  int sum;
  char s[10001];
  for(int i = 0; i < 10001; i++){
    s[i] = getchar();
    if(s[i] == '\n')break;

    if('0' <= s[i] && s[i] <= '9')sum += s[i] - '0';
  }
  printf("%d\n",sum);
}