Beautiful Permutation

You are given a permutation of the integers from 1 to \(n\). A permutation is considered beautiful if there are no two consecutive elements that form a decreasing pair. In other words, the permutation \(P = [p_1, p_2, \ldots, p_n]\) is beautiful if for every index \(i\) \( (1 \leq i < n)\), the condition \(p_i \leq p_{i+1}\) holds.

Your task is to determine whether the given permutation is beautiful.

Example

Input:
5
1 2 3 4 5
Output:
YES

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inputFormat

The input is given via STDIN and consists of two lines:

• The first line contains a single integer \(n\), the length of the permutation.
• The second line contains \(n\) space-separated integers representing the permutation.

outputFormat

Print a single line to STDOUT with the answer: print YES if the permutation is beautiful, or NO otherwise.

## sample

5
1 2 3 4 5

YES

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