Problems
Squares
Squares
Given the length of n segments. What is the maximum number of squares can be constructed? Each side of a square must be constructed from only one segment.
Input
The first line contains the number of segments n (1 ≤ n ≤ 106
). The second line contains n integers - the length of segments with values no more than 100.
Output
Print the maximum number of squares that can be constructed from the given segments.
Input example #1
9 2 2 4 2 3 2 1 2 4
Output example #1
1