Second Smallest :
Difficulty Level : Medium
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Asked In :
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You are given a list P which contains N numbers.
The element in P are permutations of numbers from 1 to N.
Your task in to calculate the number of elements ($$$P_i$$$)($$$1 \le i \le N$$$) that satisfy the following condition such that Pi is second smallest element among the three number that is ($$$p_{i-1},P_i and P_{i+1}$$$)
Input
The first line of input contains an integer N ($$$3 \le N \le 50$$$)
Next, the N line contains N integers ($$$P_i$$$)
Output
For each test case print the number of elements that is the second smallest among the three
Examples
Input
7 6 3 2 5 7 4 1
Output
3
Input
5 1 3 4 5 2
Output
2
