MAX = 10105
dp = [False] * MAX
N = int(input())
weights = list(map(int, input().split()))
sum = 0
for w in weights:
    sum += w

dp[0] = True
for i in range(N):
    for j in range(MAX - 1 - weights[i], -1, -1):
        dp[j + weights[i]] |= dp[j]

if (sum % 2 == 1) or (not dp[sum // 2]):
    print("impossible")
else:
    print("possiblle")