classmates=['a','b','c','d']
print(classmates[-1])
print(len(classmates))


classmates.append('t')
classmates.insert(1,'r')
classmates.pop()
print(classmates)

 

import turtle
turtle.speed(10)
colors=['#FF6EB4','#C67171','#CD4F39','#8968CD','#EE9A49','#FFFF00']


for i in range(200):
    turtle.pencolor(colors[i%6])
    turtle.forward(i)
    turtle.left(55)
turtle.done()

 


 

fr=open('c_kk.txt',mode='r',encoding='utf-8')
o=fr.read()
fr.close()


fw=open('kk.txt',mode='a',encoding= 'utf-8')
for c in o:
   fw.write(chr(ord(c)-3))
fw.close()