import bisect
import copy
import decimal
import fractions
import heapq
import itertools
import math
import random
import sys
from collections import Counter, deque,defaultdict
from functools import lru_cache,reduce
from heapq import heappush,heappop,heapify,heappushpop,_heappop_max,_heapify_max
def _heappush_max(heap,item):
    heap.append(item)
    heapq._siftdown_max(heap, 0, len(heap)-1)
def _heappushpop_max(heap, item):
    if heap and item < heap[0]:
        item, heap[0] = heap[0], item
        heapq._siftup_max(heap, 0)
    return item
from math import gcd as GCD
read=sys.stdin.read
readline=sys.stdin.readline
readlines=sys.stdin.readlines

N,*W=map(int,read().split())
dp=[False]*(10**4+1)
dp[0]=True
for w in W:
    for i in range(10**4,w-1,-1):
        if dp[i-w]:
            dp[i]=True
s=sum(W)
if s%2==0 and dp[s//2]:
    ans='possible'
else:
    ans='impossible'
print(ans)