n=int(input())
a=list(map(int,input().split()))
sum=sum(a)

dp=[[False]*10010 for i in range(n+1)]
dp[0][0] = True

for i in range(n):
    for j in range(10010):
        if dp[i][j] == False:
            continue
        dp[i+1][j] = True
        dp[i+1][j+a[i]] = True

if dp[-1][sum//2] == True and sum%2 == 0:
    print('possible')
else:
    print('impossible')