#include<stdio.h>
int main()
{
char s[101],out[101]="";
int seen [256]={0},i,j =0;
fgets(s,sizeof(s),stdin);
for(i=0;s[i]&&s[i]!='\n';i++)
{
if(!(s[i]>='A'&&s[i]<='Z')||(s[i]>='a'&&s[i]<='z')||(s[i]>='0'&&s[i]<='9')||(s[i]==''))
{
if(!seen[(unsigned char)s[i])
{
out[j++]=s[i];
seen[(unsigned char)s[i] =1;
}
}
}
out[j] ='\0;
printf("%s",out);
return 0;
}