A = input()
B = input()

if (A.isdigit() and B.isdigit() and A.startswith("0") == False and B.startswith("0") == False):
    if (0 <= int(A) <= 12345 and 0 <= int(B) <= 12345):
        print("OK")
    else:
        print("NG")
else:
    print("NG")