A = ['reset', 'board', 'board','reboot', 'backplane'] B =['board', 'add', 'delete', 'backplane', 'abort'] C = ['board fault', 'where to add', 'no board at all','impossible','install first'] def check(s): if len(s) == 1: if 'reset'.startswith(s[0]): return 'reset what' else: return 'unknown command' elif len(s) == 2: flag = 0 temp = [] for i, x in enumerate(A): if x.startswith(s[0]) and B[i].startswith(s[1]): flag += 1 temp.append(C[i]) if flag == 0 or flag == 2: return 'unknown command' else: return temp[0] else: return 'unknown command' while True: try: s = input().split() print(check(s)) except: break