num = int(input())

numbers = list(map(int, input().split()))

summery = 0
for number in numbers:
    summery += number

if summery % 2 == 0:
    dp = [[0 for i in range(10001)] for j in range(101)]
    dp[0][0] = 1
    for i in range(num):
        for j in range(10001):
            if dp[i][j] == 1:
                dp[i + 1][j + numbers[i]] = 1
                dp[i + 1][j] = 1
                
    if dp[num][summery // 2] == 1:
        print("possible")
    else:
        print("impossible")
else:
    print("impossible")