A = input()
B = input()

if A.isdecimal() and B.isdecimal():
    if A == str(int(A)) and B == str(int(B)):
        if int(A) <= 12345 and int(B) <= 12345:
            print('OK')
        else:
            print('NG')
    else:
        print('NG')
else:
    print('NG')