#include<stdio.h>
#include<ctype.h>
#include<string.h>
int main()
{
    char s[105];
    int seen[256]={0};
    int valid=1;
    fgets(s ,sizeof(s), stdin);
    size_t len=strlen(s);
    if(len>07&& s[len-1]=='\n') s[len-1]='\0';
    for (int i=0;s[i];i++)
    {
        if(!(isalnum(s[i])||s[i]==''))
        {
        valid=0;
        break;
        }
    }
    for(int i=0;s[i];i++)
    {
        if(!seen[(unsigned char)s[i]])
        {
            printf("%c",s[i]);
            seen[(unsigned char)s[i]]=1;
        }
    }
    printf("\n");
    return 0;
}