a=input()
b=input()
if 2<=len(a) and a[0]=="0":
    print("NG")
elif 2<=len(b) and b[0]=="0":
    print("NG")
elif a.isdigit() and b.isdigit():
    c=int(a)
    d=int(b)
    if 12345<c or 12345<d:
        print("NG")
    else:
        print("OK")
else:
    print("NG")