A = input() B = input() C = 1 if A.isdigit() == False or B.isdigit() == False: C = 0 elif (A[0] == 0 and len(A) > 1) or (B[0] == 0 and len(B) > 1): C = 0 elif int(A) > 12345 or int(B) > 12345: C = 0 print(['NG', 'OK'][C])