Hat Circle

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Time limit1sMemory limit1024 MB

Summary

Given N people in a circle with hat numbers, count how many people have the same hat number as the person directly across from them.

Level: Easy1 of 10
Topics: Array, Implementation
Solved: No attempts yet

Problem

At a recent social gathering, $N$ people sit around a circular table. $N$ is even. The seats are numbered clockwise from 1 to $N$ . The person in seat $i$ wears a hat with the number $H_i$ on it. Each person looks at the person sitting directly across from them in the circle. Determine how many people see someone wearing a hat with the same number as their own.

Input

The first line contains one even positive integer $N$ , the number of people at the gathering. Each of the next $N$ lines contains one non-negative integer $H_i$ , the hat number of person $i$ .

Output

Print a single integer: the number of people who see the same hat number as their own on the person directly across from them.

Examples2

Example 1
Input
```
4
0
1
0
1
```
Expected output
```
4
```
Example 2
Input
```
4
1
0
0
1
```
Expected output
```
0
```