import bisect,collections,itertools,math,functools,heapq
import sys
#sys.setrecursionlimit(10**6)
def I(): return int(sys.stdin.readline().rstrip())
def IN(): return int(input())
def LIN(): return list(map(int, input().split()))
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def LF(): return list(map(float,sys.stdin.readline().rstrip().split()))
def SI(): return sys.stdin.readline().rstrip()
def LS(): return list(sys.stdin.readline().rstrip().split())

"""
方針
dp
"""

N=I()
W=LI()
W.sort()
sa = sum(W)
if sa%2!=0:
    print('impossible')
    exit()

dp = [False]*(11000)
dp[0] = True
for i in range(N):
    w = W[i]
    np = dp.copy()
    for j in range(10050):
        if dp[j]:
            np[j] = True
            np[w+j] = True
    dp = np
if dp[sa//2]:
    print('possible')
else:
    print('impossible')