/**
 * ? ? ??????????????
 * ?    ?????
 * ????: 2010?11?19?
 * ???????t??????????????26?????????????????????????????????????no
*/
int main()
{
	int t, i, len;		//????t????????????len????????
	int count[26];		//??????????26????????
	char a[100000];		//??????
	cin>>t;
	while (t--)
	{
		i = 0;
		cin>>a;
		memset(count,0,sizeof(count));	//???count?????0
		len = strlen(a);		//????????
		for ( i = 0; i < len; i++ )
			count[a[i] - 'a']++;		//???????????
		for ( i = 0; i < len; i++ )
			if ( count[a[i] - 'a'] == 1 )	//??????????????????
			{
				cout<<a[i];
				break;
			}
			if ( i == len )		//?????????????????no
				cout<<"no";
			if ( t >= 0 )		
				cout<<endl;
	}
	return 0;
}
