#include<stdio.h>
#include<string.h>
#include<ctype.h>

int main()
{
char s[1000];
fgets(s,sizeof(s),stdin);
int seen[256]={0};
char result[1000];
int k=0;
for (int i=0;s[i]!='\0';i++)
{
    char c=s[i];
    if(isalnum(c)||c=='')
    {
        if(!seen[(unsigned char)c])
        {
            result[k++]=c;
            
            seen[(unsigned char)c]=1;
            
        }
    }
}
result[k]='\0';
printf("%s\n",result);
return 0;
}