import urllib.request, webbrowser
import xml.etree.ElementTree as et
arr = []
j = 1
k = input('Укажите число сообщений (по умолчанию десять): ')
rss = urllib.request.urlopen('http://l...content-available-to-author-only...a.ru/rss').read().decode()
my_tree = et.fromstring(rss)
print(' ')
print('Lenta.ru : Новости\n')
try:
        k = int(k)
except ValueError:
        k = 10
for i in my_tree:
        for elem in i.findall('item'):
                print(('---'*7+' '+  str(j) + ' ' + '---'*7).center(80))
                for q in elem.findall('pubDate'):
                        for i in q.itertext():
                                print(i)
                for q in elem.findall('title'):
                        for i in q.itertext():
                                print(i)
                for q in elem.findall('description'):
                        for i in q.itertext():
                                print(i)
                for q in elem.findall('link'):
                        for i in q.itertext():
                                print(i)
                                arr.append(i)
                j+=1
                if j == k+1:
                        break
while True:
        n = int(input("Введите номер сообщения, чтобы узнать подробности:\n ")) 
        webbrowser.open_new(arr[n-1])