Igor was bored of waiting in an airport lounge. Oceanic Airlines, a
company he didn't like so much, delayed the departure of his flight, so he was late for
the connection flight to Petrozavodsk, where a programming camp was to be held.
Now he had to wait for long 300 minutes at the airport. Soon he heard a public
announcement. Maybe, his flight had been canceled or, maybe, there were
discounts on burgers at a nearby bar—Igor couldn't tell for sure. It seemed
that the announcement had been repeated in several languages, but, strangely,
there hadn't been Russian among them.
Igor recognized the language of some of the phrases he had heard. He assumed that the
number of phrases in the announcement had been the same regardless of the
language and that the announcement had been made at most once in each language.
Help Igor to find the number of languages in which the announcement was made.
The first line contains the total number n of phrases Igor heard (2 ≤ n
≤ 1 000). In the ith of the following n lines you are given the
language of the ith phrase or the word “unknown” if Igor couldn't recognize
the language. It is guaranteed that Igor could recognize the language of at
least one of the phrases. The name of a language is a string of a length from
four to twenty symbols consisting of lowercase English letters.
Output the number of languages in which the announcement was made. If there are
several answers, list them in ascending order. If there is no solution,
output the string “Igor is wrong.”
2 3 6
Igor is wrong.
Problem Author: Denis Dublennykh
Problem Source: NEERC 2011, Eastern subregional contest