2014.Pavel and barbecue

Time Limit: 1s Memory Limit: 256MB

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 \ge 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.

Input Format(From the terminal/stdin)

The first line contain the integer n (1 \le n \le 2 \cdot 105)- the number of skewers.

The second line contains a sequence of integers p1,p2,...,pn (1 \le pi \le 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.

Output Format(To the terminal/stdout)

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.

Sample Input 1

Copy
4
4 3 2 1
0 1 1 1
 \n
 · · · \n
 · · · \n

Sample Output 1

Copy
2
 \n

Sample Input 2

Copy
3
2 3 1
0 0 0
 \n
 · · \n
 · · \n

Sample Output 2

Copy
1
 \n

Hints

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.

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