#include <cstdio>
#include <cstdlib>
#include <cctype>
#include <string>

int ctoi(const char c)
{
  switch(c){
  case '0': return 0;
  case '1': return 1;
  case '2': return 2;
  case '3': return 3;
  case '4': return 4;
  case '5': return 5;
  case '6': return 6;
  case '7': return 7;
  case '8': return 8;
  case '9': return 9;
  default : return 0;
  }
}

int str2sum(char *str)
{
  int sum = 0;
  for(int i=0;;i++){

    if ( str[i] == '\0' ){
      break;
    }
    
    if ( isdigit(str[i]) ){
      sum += ctoi(str[i]);
    }
    
  }
  return sum;
}

int main(void)
{
  int a;
  char input[10000];
  scanf("%s",input);
  a = str2sum(input);
  printf("%d\n",a);
  return 0;
}