#!/usr/bin/sed -nf
#
# Carlos J.Duarte

# first line is pasted into buffer
1{
	h
	b
}

# for all other lines, the buffer (which contains all previous) 
# is appended to current line, so, the order is being reversed
# on the buffer, after that is done, store everything on the buffer
# again
G
h

# the last line (after have done the above job) get the contents
# of buffer, and print it
${
	g
	p
}