"""
Yukicoder No. 004 おもりと天秤

author: yamaton
date: 2015-12-18
"""

import itertools
import collections
import sys

def solve(xs, n):
    total = sum(xs)
    if total % 2 == 1:
        return False
    goal = total // 2

    accum_weights = collections.defaultdict(int)
    for x in xs:
        for w in list(accum_weights):
            accum_weights[x + w] += 1
        accum_weights[x] += 1
    return accum_weights[goal] > 0


def pp(*args, **kwargs):
    return print(*args, file=sys.stderr, **kwargs)


def tf2msg(tf):
    return 'possible' if tf else 'impossible'


def main():
    n = int(input())
    xs = [int(i) for i in input().split()]
    assert len(xs) == n
    result = tf2msg(solve(xs, n))
    print(result)


if __name__ == '__main__':
    main()