A = input()
B = input()
if len(A) >= 2 and A[0] =="0":
    print("NG")
elif len(B) >= 2 and B[0] =="0":
    print("NG")
elif A.isdigit() == True and 0 <= int(A) <= 12345:
    if B.isdigit() == True and 0 <= int(B) <= 12345:
        print("OK")
    else:
        print("NG")
else:
    print("NG")