#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>


int main() {
  system("cls");
  //INPUT - @STUDENT:ADD YOUR CODE FOR INPUT HERE:

  char s[100];
  int a[100000];

  for (int i=0;i<=100000;i++)
    a[i]=0;

  gets(s);
  for (int i=0;i<=strlen(s)-1;i++)
    {
        int x=s[i];
        a[x]=a[x]+1;
    }




  // Fixed Do not edit anything here.
  printf("\nOUTPUT:\n");
  //@STUDENT: WRITE YOUR OUTPUT HERE:

for (int i=0;i<=strlen(s)-1;i++)
    if (a[s[i]]==1)
        printf("%c",s[i]);







  //--FIXED PART - DO NOT EDIT ANY THINGS HERE
  printf("\n");
  system ("pause");
  return(0);
}