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 C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Net.Mail;

namespace Contest
{
    class Scanner
    {
        private string[] line = new string[0];
        private int index = 0;
        public string Next()
        {
            if (line.Length <= index)
            {
                line = Console.ReadLine().Split(' ');
                index = 0;
            }
            var res = line[index];
            index++;
            return res;
        }
        public int NextInt()
        {
            return int.Parse(Next());
        }
        public long NextLong()
        {
            return long.Parse(Next());
        }
        public string[] Array()
        {
            line = Console.ReadLine().Split(' ');
            index = line.Length;
            return line;
        }
        public int[] IntArray()
        {
            var array = Array();
            var result = new int[array.Length];
            for (int i = 0; i < array.Length; i++)
            {
                result[i] = int.Parse(array[i]);
            }

            return result;
        }
        public long[] LongArray()
        {
            var array = Array();
            var result = new long[array.Length];
            for (int i = 0; i < array.Length; i++)
            {
                result[i] = long.Parse(array[i]);
            }

            return result;
        }
    }

    class UnionFind
    {
        private int[] Par, Rank;
        public UnionFind(int max)
        {
            Par = new int[max];
            Rank = new int[max];
            for (int i = 0; i < max; i++)
            {
                Par[i] = i;
            }
        }

        private int Find(int n)
        {
            if (Par[n] == n)
            {
                return n;
            }
            else
            {
                return Find(Par[n]);
            }
        }

        public bool Same(int a, int b)
        {
            return Find(a) == Find(b);
        }

        public void Union(int a, int b)
        {
            a = Find(a);
            b = Find(b);
            if (a == b) return;
            if (Rank[a] < Rank[b])
            {
                Par[a] = b;
            }
            else
            {
                Par[b] = a;
                if (Rank[a] == Rank[b]) Rank[a]++;
            }
        }
    }


    class Program
    {
        private int N, M;
        private int[] P;
        private int[] X, Y;
        private void Scan()
        {
            var sc = new Scanner();
            N = sc.NextInt();
            M = sc.NextInt();
            P = sc.IntArray();
            X = new int[M];
            Y = new int[M];
            for (int i = 0; i < M; i++)
            {
                X[i] = sc.NextInt() - 1;
                Y[i] = sc.NextInt() - 1;
            }
        }

        public void Solve()
        {
            Scan();
            var uf = new UnionFind(N);
            var index = new int[N];
            for (int i = 0; i < N; i++)
            {
                P[i]--;
                index[P[i]] = i;

            }
            for (int i = 0; i < M; i++)
            {
                uf.Union(X[i], Y[i]);
            }

            int cnt = 0;
            for (int i = 0; i < N; i++)
            {
                if (uf.Same(i, index[i])) cnt++;
            }
            Console.WriteLine(cnt);
        }

        static void Main(string[] args)
        {
            new Program().Solve();
        }
    }
}