Counting Good Pairs

You are given an array of n integers. A pair of indices \((i, j)\) is called good if \(i < j\) and \(a_i = a_j\). Your task is to count the total number of good pairs in the array.

Mathematical Formulation:

Find the number of pairs \((i, j)\) such that

$$i < j \quad \text{and} \quad a_i = a_j.$$

Example:

Input: 6
       1 2 3 1 1 3
Output: 4

inputFormat

The first line contains a single integer n, the number of elements in the array.

The second line contains n space-separated integers representing the elements of the array.

outputFormat

Print a single integer representing the total number of good pairs in the array.

## sample

6
1 2 3 1 1 3

4

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