#include<stdio.h>
#include<ctype.h>
int main(){
    char s[105],seen[256]={0};
    if(!fgets(s,sizeof(s),stdin))return 0;
    s[strcspn(s,"\n")]=0;
    for(int i=0;s[i];i++){
        if(!(isalnum((unsigned char)s[i])||s[i]=='-')){
            printf("Invalid input\n");
            return 0;
        }
    char c= tolower((unsigned char)s[i]);
    if(!seen[(unsigned char)c]){
        putchar(c);
        seen[(unsigned char)c]=1;
        }
    }
    return 0;
}