l = [0,0]
flg = 0

for i in range(2):
    try:
        ck = input()
        l[i] = int(ck)
        ck1 = str(l[i])
        if len(ck) != len(ck1) or l[i] > 12345:
            flg = 1
    except:
        flg = 1

if flg == 0:
    print("OK")
else:
    print("NG")