#include<bits/stdc++.h>
using namespace std;
int main()
{
int test;
cin>>test;
while(test--)
{
string str;
cin>>str;
int c,d,l,cnt=0,ele=0;
l=str.length();
for(c=0;c<l;c++)
{
cnt=0;
for(d=0;d<l;d++)
{
if(str[d]==str[c])
{
cnt++;
}
}
if(cnt>1)
{
ele=str[c];
break;
}
}
if(cnt==0 || ele==0)
{
cout<<".\n";
}
else
{
cout<<(char)ele<<"\n";
}
}
return 0;
}
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