# Squares

Very easy

Execution time limit is 2 seconds

Runtime memory usage limit is 128 megabytes

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 $n(1≤n≤10_{6})$. 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.

## Examples

Input #1

Answer #1

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Acceptance rate 44%