#include<stdio.h>
#include<ctype.h>
#include<string.h>
int main(){
char s[101];
fgets(s,sizeof(s),stdin);
s[strcspn(s, "\n")]=0;
int seen[256]={0};
char result[101];
int k=0;
for(int i = 0;s[i];i++){
    char c=s[i];
    if(!(isalnum(c)||isspace(c)){
    if(!seen[(unsigned char)c]){
        result[k++]=c;
        seen[(unsigned char)c]=1;
    }
} else{
    prinf("Invalid Input\n");
    return 0;
  }
}
result[k]='\0';
printf("%s" , result);
return 0;
}