Problem:
Score : 400 points

Problem Statement

We have a permutation of the integers from 1 through N, p_1, p_2, .., p_N.
We also have M pairs of two integers between 1 and N (inclusive), represented as (x_1,y_1), (x_2,y_2), .., (x_M,y_M).
AtCoDeer the deer is going to perform the following operation on p as many times as desired so that the number of i (1 ≤ i ≤ N) such that p_i = i is maximized:

Choose j such that 1 ≤ j ≤ M, and swap p_{x_j} and p_{y_j}.

Find the maximum possible number of i such that p_i = i after operations.

Constraints

2 ≤ N ≤ 10^5

1 ≤ M ≤ 10^5

p is a permutation of integers from 1 through N.

1 ≤ x_j,y_j ≤ N

x_j ≠ y_j

If i ≠ j, \{x_i,y_i\} ≠ \{x_j,y_j\}.

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N M
p_1 p_2 .. p_N
x_1 y_1
x_2 y_2
:
x_M y_M

Output

Print the maximum possible number of i such that p_i = i after operations.

Sample Input 1

5 2
5 3 1 4 2
1 3
5 4

Sample Output 1

2

If we perform the operation by choosing j=1, p becomes 1 3 5 4 2, which is optimal, so the answer is 2.

Sample Input 2

3 2
3 2 1
1 2
2 3

Sample Output 2

3

If we perform the operation by, for example, choosing j=1, j=2, j=1 in this order, p becomes 1 2 3, which is obviously optimal.
Note that we may choose the same j any number of times.

Sample Input 3

10 8
5 3 6 8 7 10 9 1 2 4
3 1
4 1
5 9
2 5
6 5
3 5
8 9
7 9

Sample Output 3

8

Sample Input 4

5 1
1 2 3 4 5
1 5

Sample Output 4

5

We do not have to perform the operation.

Solution in Python (3.4.3) (judge verdict: Time Limit Exceeded)

n, m = map(int, input().split())
p = list(map(int, input().split()))
g = []
for i in range(m):
    g.append(list(map(int, input().split())))
l = [[] for i in range(n+1)]
for pi in g:  
    l[pi[0]].append(pi[1])
    l[pi[1]].append(pi[0])
x =  [0]*n
for i in range(n):
  x[p[i]-1] = i+1
ans = 0
#Union find
y = [-1] * n
for i in range(0,n):
  if y[i] == -1:
    y[i] = i
  c = l[i+1]
  while len(c) > 0:
    z = c.pop()
    y[z-1] = y[i]
    for j in range(len(l[z])):
      if y[l[z][j]-1] == -1:
        c.append(l[z][j])
    
for i in range(n):
  c = x[i]
  if y[c-1] == y[i]:
    ans +=1
print(ans)