#include <stdio.h>
int main (void)
{

  int i;
  int sum=0;
  char S[9999] = {"\0"};
  scanf("%s",S);

  for(i=0;i<=9999;i++){

    if(S[i]>='0'&&S[i]<='9'){
      sum = sum +S[i] - '0';
    }
  }

  printf("%d\n",sum);
  return 0;

}