N = int(input()) weights_list = [0] + list(map(int, input().split(' '))) total = sum(weights_list) if total % 2 == 1: print("impossible") exit() #dp = np.zeros((N + 1, 10001), dtype=np.bool) dp = [[0] * (10001) for _ in range(N + 1)] dp[0][0] = True for i in range(1, N + 1): for j in range(10001): if (dp[i-1][j] == True) or ((j >= weights_list[i]) and (dp[i-1][j-weights_list[i]] == True)): dp[i][j] = True if dp[-1][total // 2]: print("possible") else: print("impossible")