A = gets.split.map(&:to_i)

B = A.uniq.sort
a = A.map { B.index(_1) }

(1 << a.size).times do |bits|
    p, q, r, s, t, u = a.map { bits[_1] == 1 }
    if !(!(!(p & q) & r) & !(!(s & t) & u))
        puts "YES"
        exit
    end
end

puts "NO"