SP25179 KAOS - Kaos

**kaos** Little Lovro likes to play games with words. During the last few weeks he realized that some words don't like each other. The words A and B **don't like** each other if **the word A is lexicographically before the word B**, but **the word B' is lexicographically before the word A'**, where X' stands for the word X reversed (if X = “kamen”, then X' = “nemak”). For example, the words “lova” and “novac” like each other, but the words “aron” and “sunce” don't like each other. Given some set of the words, we define **the degree** **of chaos** of the set as **the number of pairs** of different words that **don't** like each other. Write a program that, given a set of words, finds the chaos degree for the set. **input data** The first line of input contains an integer _N_, 2 N Each of the following _N_ lines contains one word – a sequence of at most 10 lowercase letters of the English alphabet ('a' – 'z'). There will be no two identical words in the set. **output data** The first and only line of output should contain a single integer – the chaos degree of the given set of words. **Note:** use 64-bit signed integer type (int64 in Pascal, long long in C/C++) **examples** **input input input** 2 4 14 lopta lova branimir kugla novac vladimir aron tom **output** sunce kruz 0 bred **output** pit 3 zemlja nije ravna ploca ko je zapalio zito **output** 48

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