# Sales by Match

Alex works at a clothing store. There is a large pile of socks that must be paired by color for sale. Given **an array of integers representing the color of each sock**, determine **how many pairs of socks with matching colors there are**.

For example, there are *n = 7* socks with colors *ar = [1,2,1,2,1,3,2]*. There is one pair of color **1** and one of color **2**.  

The number of pairs is **2**.