def balance(weights):
    n = len(weights)  
    total_sum = sum(weights)

    if total_sum % 2 == 1:  
        return "impossible"

    dp = [[False] * 10009 for _ in range(n + 1)]
    dp[0][0] = True  

    for i in range(n):
        for j in range(10000 + 1):
            if not dp[i][j]:
                continue
            dp[i + 1][j] = True  
            dp[i + 1][j + weights[i]] = True  

    return "possible" if dp[n][total_sum // 2] else "impossible"

n = int(input())
weights = list(map(int, input().split()))
print(balance(weights))