In which practice section is this problem “Let us construct palindromes - PRPALN”?
There are some problem with moving problems to practice section, your problem is here - http://www.codechef.com/problems/PRPALN
I answered similar question here - http://discuss.codechef.com/questions/55531/how-to-search-for-a-problem-in-practice-section?page=1#55535