#region Header
#!/usr/bin/env python3
# from typing import *

import sys
import io
import math
import collections
import decimal
import itertools
from queue import PriorityQueue
import bisect
import heapq

def input():
    return sys.stdin.readline()[:-1]

sys.setrecursionlimit(1000000)
#endregion

# _INPUT = """# paste here...
# """
# sys.stdin = io.StringIO(_INPUT)

YES = 'possible'
NO = 'impossible'


def main():
    N = int(input())
    W = list(map(int, input().split()))

    SumW = sum(W)
    if SumW % 2 == 1:
        print(NO)
        return

    dp = [[False for _ in range(SumW+1)] for _ in range(N+1)]
    dp[0][0] = True
    for i in range(N):
        for w in range(SumW+1):
            if dp[i][w]:
                dp[i+1][w] = True
                dp[i+1][w+W[i]] = True

    if dp[N][SumW//2]:
        print(YES)
    else:
        print(NO)


if __name__ == '__main__':
    main()