修好之前和之后，读得到几个

运行下面这段程序，填写它打印出来的结果。

def cls(uid, gid, f_uid, f_gid):
    if uid == f_uid:
        return 0
    if gid == f_gid:
        return 1
    return 2

def can(mode, k, op):
    digit = (mode >> (3 * (2 - k))) & 7
    bit = {"r": 4, "w": 2, "x": 1}[op]
    return digit & bit != 0

files = [0o644, 0o664, 0o640, 0o600, 0o644, 0o604, 0o044]
before = sum(1 for m in files if can(m, 0, "r"))
after = sum(1 for m in files if can(m | 0o400, 0, "r"))
print(str(len(files)) + "/" + str(before) + "/" + str(after))