# https://open.kattis.com/problems/nodup
# 1s
# 1.5 Easy


# 39 chars
puts ((x=gets.split).uniq==x)?:yes: :no


# 39 chars Top 10 place 4
# x=gets.split
# puts (x.uniq==x)?:yes: :no

# 40 chars
# $><<(((x=gets.split).uniq==x)?:yes: :no)

# 41 chars Top 10 place 6
# x=gets.split
# puts (x.uniq==x)? "yes":"no"