import sys def main(): N = int(input()) li = list(map(int,input().split())) total = 0 for i in range(len(li)): total += li[i] for i in range(len(li)): if(li[i] > (total / 2)): print("out") sys.exit() if((total % 2) != 0): print("out") sys.exit() print("ok") if __name__ == '__main__': main()