#include<stdio.h>
#include<string.h>
#include<ctype.h>
int main(){
    char s[1000],result[1000];
    int seen[256]={0};
    int i,j=0;
    fgets(s,sizeof(s),stdin);
    for(i=0;s[i]!='\0';i++){
        char c=s[i];
        if(isalnum(c)||c==''){
            if(!seen[(unsigned char)c]){
                result[j++]=c;
                seen[(unsigned char)c]=1;
            }
        }
    }
    result[j]='\0';
    printf("%s\n",result);
    return 0;
    
}