Pavel cooks barbecue. There are n skewers, they lay on a brazier in a row, each on one of n positions. Pavel wants each skewer to be cooked some time in every of n positions in two directions: in the one it was directed originally and in the reversed direction.
Pavel has a plan: a permutation p and a sequence b1,b2,...,bn, consisting of zeros and ones. Each second Pavel move skewer on position i to position pi, and if bi equals 1 then he reverses it. So he hope that every skewer will visit every position in both directions.
Unfortunately, not every pair of permutation p and sequence b suits Pavel. What is the minimum total number of elements in the given permutation p and the given sequence b he needs to change so that every skewer will visit each of 2n placements? Note that after changing the permutation should remain a permutation as well.
There is no problem for Pavel, if some skewer visits some of the placements several times before he ends to cook. In other words, a permutation p and a sequence b suit him if there is an integer k (k≥2n), so that after k seconds each skewer visits each of the 2n placements.
It can be shown that some suitable pair of permutation p and sequence b exists for any n.
The first line contain the integer n (1≤n≤2·105)− the number of skewers.
The second line contains a sequence of integers p1,p2,...,pn (1≤pi≤n)− the permutation, according to which Pavel wants to move the skewers.
The third line contains a sequence b1,b2,...,bn consisting of zeros and ones, according to which Pavel wants to reverse the skewers.
Print single integer− the minimum total number of elements in the given permutation p and the given sequence b he needs to change so that every skewer will visit each of 2n placements.
4
4 3 2 1
0 1 1 1
2
3
2 3 1
0 0 0
1
In the first example Pavel can change the permutation to 4,3,1,2.
In the second example Pavel can change any element of b to 1.