import sys
from collections import deque, defaultdict,Counter
from copy import deepcopy
from bisect import bisect_left, bisect_right, insort_left, insort_right
from heapq import heapify, heappop, heappush
from itertools import product, permutations, combinations, combinations_with_replacement,accumulate
from functools import reduce
from math import gcd, sin, cos, tan, asin, acos, atan, degrees, radians, ceil, floor, log, sqrt, ceil, floor, pi, hypot
from string import ascii_lowercase
from decimal import Decimal, ROUND_HALF_UP, ROUND_HALF_EVEN
sys.setrecursionlimit(1000000)
INF = 10**18
MOD = 10**9+7
# MOD = 998244353
yes="Yes"
no="No"
from random import randint
def II():return int(input())
def SI():return str(input())
def MI():return map(int,input().split())
def MS():return map(str,input().split())
def LI():return list(map(int,input().split()))
def SLI():return sorted(list(map(int,input().split())))
n=II()
w=LI()
wsum=sum(w)
if wsum%2:
    print("impossible")
    exit()
wsum//=2
dp=[[False]*11000 for i in range(n+1)]
dp[0][0]=True
for i in range(n):
    for j in range(11000):
        dp[i+1][j]|=dp[i][j]
        if j-w[i]>=0:
            dp[i+1][j]|=dp[i][j-w[i]]
print("possible" if dp[n][wsum] else "impossible")