Python , Web Parsing

I was watching a tutorial on web paring in python .

   import re
   import urllib.request

    # http://ift.tt/TcXbw1
    url = "http://ift.tt/TcXbw1"
    stock = input("Enter Your Stock : ")
    url = url + stock
    data = urllib.request.urlopen(url).read()
    newData = data.decode('utf-8')
    # meta itemprop="price"
    m = re.search('meta itemprop="price"', newData)
    start = m.start()
    end = start + 50
    newStock = newData[start:end]
    m = re.search('content="', newStock)
    start = m.end()
    newStock1 = newStock[start:]
    m = re.search('/', newStock1)
    start = 0
    end = m.end() - 3
    final = newStock1[0:end]
    print("The Value Of " + stock + " Is " + final)

There is no error but I dont understand these parts :

    start = m.start()
     end = start + 50 

    start = 0
   end = m.end() - 3

Can anyone give me an explanation ? Please elaborate