<?php
$n = trim(fgets(STDIN));
$v = explode(' ', (trim(fgets(STDIN))));
$sum = array_sum($v);
$dp=array_fill(0,10000,0);
$dp[0] = $v[0];
for ($i=0; $i < $n-1; $i++){
	for ($j=$sum -$dp[$i]; $j> -1; $j--){
		if ($dp[$j] > 0){
			$dp[$j + $v[$i]] = 1;
		}
	}
}
if ($sum%2 == 0 and $dp[floor($sum/2)]){
	echo 'possible' . PHP_EOL;
} else {
	echo 'impossible' . PHP_EOL;
}