#include <stdio.h>

int n, i, ans, a[100], dp[100][100] = { 0 };

int solve(int i, int m)
{
	if (dp[i][m] != 0) return dp[i][m];
	if (m == 0) dp[i][m] = 1;
	else if (i >= n) dp[i][m] = 0;
	else if (solve(i + 1, m) || solve(i + 1, m - a[i])) dp[i][m] = 1;
	else dp[i][m] = 0;
	return dp[i][m];
}

int main(void)
{
	scanf("%d", &n);

	for (i = 0; i<n; i++)
	{
		scanf("%d", &a[i]);
		ans += a[i];
	}

	if (ans % 2 == 0&& solve(0, ans / 2)) printf("possible\n");
	else printf("impossible\n");

	return 0;
}