//****************************************
//*????????????                                    **
//*????? 1000012916       **
//*???2011. 11.4                         **
//****************************************
int main()
{
    int t = 0, i = 0, j = 0, k = 0, p = 0, len = 0, flag = 0;//???????flag?????????????
	int b[26] = {0};//?????????????
	char str[100000] = {0}, c[1000] = {0};
	cin >> t;
	for (i = 0; i < t;i++)
	{
		cin >> str;
        len = strlen (str);//??????????????
		for (j = 0; j < len; j++)  
            b[str[j] - 'a'] +=1;//?char???int??????????b???
		for (j = 0; j < 26; j++)
		{
			if (b[j] == 1)
			c[k++] = j + 'a';//??????????
		}
		if (k == 0)//????????
			cout << "no" << endl;
		else
		{
			for (j = 0; j < len; j++)//????????????
			{
				for (p = 0; p < k; p++)
				{
					if (c[p] == str[j])
					{
						cout << c[p] << endl;
						flag = 1;//??????????
						break;
					}
					if( flag == 1)
						break;

				}
				if(flag == 1)
					break;
			}
		}
		memset(str, 0, sizeof(str));//????
		memset(c, 0, sizeof(c));
		memset(b, 0, sizeof(b));
		j = 0;
		k = 0;
		p = 0;
		flag = 0;

	}
	return 0;
}



