N=gets.to_i
A=[0]+gets.split.map(&:to_i)
puts (1..N).map{|i|t=[j=i];t<<j until(j=A[j];j==i);t.sort}.uniq.group_by{|i|i.size}.all?{|k,v|k%2>0||v.size%2<1}?:Yes:"No"