#5715. Permutation Rounds
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Permutation Rounds
Permutation Rounds
There is a sorted array [1,2,\dots,n] and a permutation p_1,p_2,\dots,p_n. On each round, all elements move according to the permutation: the element at position i moves to position p_i. After how many rounds is the array sorted again for the first time?
Input
The first line has an integer n. The next line contains n integers p_1,p_2,\dots,p_n.
Output
Print the number of rounds modulo 10^9+7.
Constraints
\cdot 10^5$
Example
Input
8
5 3 2 6 4 1 8 7
Output
4
Explanation: The array changes as follows after the rounds:
Round 1: [6,3,2,5,1,4,8,7]
Round 2: [4,2,3,1,6,5,7,8]
Round 3: [5,3,2,6,4,1,8,7]
Round 4: [1,2,3,4,5,6,7,8]