A = input()
B = input()

try :
    a = int(A)
    if str(a) != A :
        print("NG")
        exit()
    elif (a < 0) or (a > 12345) :
        print("NG")
        exit()
except Exception as error :
    print("NG")
    exit()

try :
    b = int(B)
    if str(b) != B :
        print("NG")
        exit()
    elif (b < 0) or (b > 12345) :
        print("NG")
        exit()
except Exception as error :
    print("NG")
    exit()

print("OK")