#coding=utf-8

# 条件转化

data=raw_input("enter 'y' or 'n'")

if data[0]=='y':

	print "you typed y."

elif data[0]=='n':

	print "you typed n."

else:

	print 'invalid key entered!'

# 循环

i=0

while i<5:

	print i

	i+=1