CF285C Building Permutation

Permutation $ p $ is an ordered set of integers $ p_{1},p_{2},...,p_{n} $ , consisting of $ n $ distinct positive integers, each of them doesn't exceed $ n $ . We'll denote the $ i $ -th element of permutation $ p $ as $ p_{i} $ . We'll call number $ n $ the size or the length of permutation $ p_{1},p_{2},...,p_{n} $ . You have a sequence of integers $ a_{1},a_{2},...,a_{n} $ . In one move, you are allowed to decrease or increase any number by one. Count the minimum number of moves, needed to build a permutation from this sequence.

The first line contains integer $ n $ ( $ 1

Print a single number — the minimum number of moves. Please, do not use the %lld specifier to read or write 64-bit integers in C++. It is preferred to use the cin, cout streams or the %I64d specifier.

In the first sample you should decrease the first number by one and then increase the second number by one. The resulting permutation is $ (2,1) $ . In the second sample you need 6 moves to build permutation $ (1,3,2) $ .