def day5():
    if not os.path.isfile(OUTPUT_FNAME):
        print("downloading " + INPUT_URL)
        opener = urllib.request.build_opener()
        opener.addheaders.append(('Cookie', 'session=' + COOKIE))
        k = opener.open(INPUT_URL)
        with open(OUTPUT_FNAME, "w") as f:
            f.write(k.read().decode("utf-8"))

    with open(OUTPUT_FNAME) as f:
        foo = f.read().replace('\n','')

        winchar = ''
        scores = []

        def ex(foo,c):
            print('beginning: c=' + str(c))
            tw = testwithout(foo.replace(c,'').replace(c.upper(),''))
            print('c=' + str(c) + ' tw=' + str(tw))
            scores.append((c,tw))

        NUM_THREADS = 4
        chrs = "qwertyuiopasdfghjklzxcvbnm"
        for s in [chrs[j:(j+NUM_THREADS)] for j in range(0, len(chrs), NUM_THREADS)]:
            threads = [threading.Thread(target=ex, args=(foo,c)) for c in s]
            [t.start() for t in threads]
            [t.join() for t in threads]

        lowest = 999999999
        lowestc = ''
        for s in scores:
            if s[1] < lowest:
                lowest = s[1]
                lowestc = s[0]
        print(lowestc)
        print(str(lowest))