line1 = gets.chomp!
line2 = gets.chomp!
abort "eof" if gets
abort "l1" unless line1 =~ /^[0-9]+ [0-9]+$/
abort "l2" unless line2 =~ /^[0-9]+( [0-9]+)*$/
n,m = line1.split.map(&:to_i)
aa = line2.split.map(&:to_i)
abort "n" unless 3 <= n && n <= 100000
abort "m" unless 1 <= m && m <= 100000
abort "aa.size" unless aa.size != n
abort "aa" unless aa.all?{|a| 1 <= a && a <= m}