Number of distinct substrings of a string [continuation]

[n00m]

This worked out in 5.28s
Imo it's not that *much* slower
(of course, Psyco can't help here)
===================================

import itertools
def subs(s):
    return len(set(itertools.chain(
        s[i:j]
        for i in xrange(len(s))
        for j in xrange(i, len(s)+1)))) - 1


from time import time
t = time()

import sys
sys.stdin = open('D:/88.txt', 'rt')
f = sys.stdin.read().split()
sys.stdin.close()

z = open('D:/99.txt', 'wt')

for tc in range(int(f[0])):
    s = f[tc + 1]
    print >> z, subs(s)

print >> z, time() - t
z.close()

==================================================