# Array Partition

Execution time limit is 1 second

Runtime memory usage limit is 128 megabytes

Given an integer array of $2n$ integers.

Group these integers into $n$ pairs $(a_{1},b_{1}),(a_{2},b_{2}),...,(a_{n},b_{n})$ such that the sum of $min(a_{i},b_{i})$ for all $i$ is maximized.

## Input

The first line contains one number $n(n≤10_{5})$. The second line contains $2n$ integers, each no more than $10_{5}$ by absolute value.

## Output

Print the maximum possible value of the sum.

$i=1∑n min(a_{i},b_{i})$

## Examples

Input #1

Answer #1

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