from typing import List


def f(n: int, ws: List[int]) -> bool:
    max_w = sum(ws)
    if max_w % 2 != 0:
        return False

    half_w = int(max_w / 2)
    dp = [[False] * (half_w + 1) for _ in range(0, n + 1)]
    dp[0][0] = True

    for i in range(0, n):
        for w in range(0, half_w + 1):
            dp[i + 1][w] = (
                (dp[i][w - ws[i]] or dp[i][w]) if w >= ws[i] else dp[i][w]
            )

    return dp[n][half_w]


# assert f(3, [1, 2, 3])
# assert not f(5, [1, 2, 3, 4, 5])
# assert not f(15, [62, 8, 90, 2, 24, 62, 38, 64, 76, 60, 30, 76, 80, 74, 72])

n = int(input())
ws = list(map(int, input().split(" ")))
print("possible" if f(n, ws) else "impossible")