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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;

public class Main {
	public static void main(String[] args) {
		new Main().solve();
	}

	/**
	 * ASCII
	 * 0 48
	 * A 65
	 * a 97
	 */

	static PrintWriter pw = new PrintWriter(System.out);

	void solve() {
		FastScanner sc = new FastScanner();
		int N = sc.nextInt();
		int M = sc.nextInt();
		p = new int[N+1];
		for (int i = 1; i <= N; i++) p[i] = sc.nextInt();
		nodes = new List[N+1];
		for (int i = 1; i <= N; i++) {
			nodes[i] = new ArrayList<Integer>();
			nodes[i].add(i);
		}
		for (int i = 0; i < M; i++) {
			int x = sc.nextInt();
			int y = sc.nextInt();
			nodes[x].add(y);
			nodes[y].add(x);
		}
		sets = new Set[N+1];
		for (int i = 1; i <= N; i++) {
			if (sets[i] == null) {
				Set<Integer> set = new HashSet<Integer>();
				sets[i] = set;
				func(i, set, new boolean[N+1]);
			}
		}
		int ans = 0;
		for (int i = 1; i <= N; i++) {
			if (sets[i].contains(i)) ans++;
		}
		out(ans);
		pw.close();
	}
	
	int[] p;
	List<Integer>[] nodes;
	Set<Integer>[] sets;


	void func(int num, Set<Integer> set, boolean[] b) {
		b[num] = true;
		set.add(p[num]);
		for (int t : nodes[num]) {
			if (b[t]) continue;
			sets[t] = set;
			func(t, set, b);
		}
	}

	class Combination {
		final int mod;
		final int max;

		final long[] fact;
		final long[] inv;
		final long[] invfact;

		public Combination(int n) {
			this(n, 1_000_000_007);
		}

		public Combination(int n, int mod) {
			this.mod = mod;
			max = n + 1;
			fact = new long[max];
			invfact = new long[max];
			inv = new long[max];

			inv[1] = 1;
			for (int i = 2; i < inv.length; i++) {
				inv[i] = inv[mod % i] * (mod - mod / i) % mod;
			}

			fact[0] = 1;
			invfact[0] = 1;
			for (int i = 1; i < inv.length; i++) {
				fact[i] = i * fact[i - 1] % mod;
				invfact[i] = inv[i] * invfact[i - 1] % mod;
			}
		}

		public long get(int n, int r) {
			return fact[n] * invfact[n - r] % mod * invfact[r] % mod;
		}
	}

	public long gcd(long a, long b) {
		if (b == 0) return a;
		else return gcd(b, a%b);
	}

	void out(String a) {
		pw.println(a);
	}
	void out(boolean a) {
		pw.println(a);
	}

	void out(int a) {
		pw.println(a);
	}

	void out(long a) {
		pw.println(a);
	}

	void out(double a) {
		pw.println(a);
	}

	void out(char a) {
		pw.println(a);
	}

	void rout(String a) {
		out(a);
		pw.close();
		System.exit(0);
	}
	void rout(int a) {
		out(a);
		pw.close();
		System.exit(0);
	}
	void rout(long a) {
		out(a);
		pw.close();
		System.exit(0);
	}
	void rout(double a) {
		out(a);
		pw.close();
		System.exit(0);
	}
	void rout(char a) {
		out(a);
		pw.close();
		System.exit(0);
	}
}


class FastScanner {
    private final InputStream in = System.in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;
    private boolean hasNextByte() {
        if (ptr < buflen) {
            return true;
        } else {
            ptr = 0;
            try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (buflen <= 0) {
                return false;
            }
        }
        return true;
    }

    private int readByte() {
        if (hasNextByte())
            return buffer[ptr++];
        else
            return -1;
    }

    private boolean isPrintableChar(int c) {
        return 33 <= c && c <= 126;
    }

    public boolean hasNext() {
        while (hasNextByte() && !isPrintableChar(buffer[ptr]))
            ptr++;
        return hasNextByte();
    }

    public String next() {
        if (!hasNext())
            throw new NoSuchElementException();
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while (isPrintableChar(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }

    public long nextLong() {
        if (!hasNext())
            throw new NoSuchElementException();
        long n = 0;
        boolean minus = false;
        int b = readByte();
        if (b == '-') {
            minus = true;
            b = readByte();
        }
        if (b < '0' || '9' < b) {
            throw new NumberFormatException();
        }
        while (true) {
            if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            } else if (b == -1 || !isPrintableChar(b)) {
                return minus ? -n : n;
            } else {
                throw new NumberFormatException();
            }
            b = readByte();
        }
    }

    public int nextInt() {
        long nl = nextLong();
        if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE)
            throw new NumberFormatException();
        return (int) nl;
    }

    public double nextDouble() {
        return Double.parseDouble(next());
    }
}