arr = [1, 2,3]
arr. append (4)
arr. append (5)
arr.pop ()
arr. append (6)
arr. append (7)
arr. pop ()
print (arr)
YXJyID0gWzEsIDIsM10KYXJyLiBhcHBlbmQgKDQpCmFyci4gYXBwZW5kICg1KQphcnIucG9wICgpCmFyci4gYXBwZW5kICg2KQphcnIuIGFwcGVuZCAoNykKYXJyLiBwb3AgKCkKcHJpbnQgKGFycikKCiAgICAKICAgIA==