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 (GCC 5.4.1) (judge verdict: Accepted)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define ll long long
#define rep(i,l,r)for(ll i=(l);i<(r);i++)
#define LIMIT 100010
//union-find
int uniroot[LIMIT+10],unicnt[LIMIT+10];
void ufinit(int n){for(int i=0;i<n;i++){uniroot[i]=i;}}//unicnt[i]=1;}}
int root(int x){return uniroot[x]!=x?uniroot[x]=root(uniroot[x]):x;}
int same(int x,int y){return root(x)==root(y);}
void uni(int x,int y){if((x=root(x))==(y=root(y)))return;uniroot[x]=y;}//unicnt[y]+=unicnt[x];}

int a[100010];
int main(){
	int n,m;
	scanf("%d%d",&n,&m);
	ufinit(n+1);
	rep(i,0,n){
		int t;
		scanf("%d",&t);
		a[t]=i+1;
	}
	rep(i,0,m){
		int p,q;
		scanf("%d%d",&p,&q);
		uni(p,q);
	}
	ll ans=0;
	rep(i,1,n+1)if(same(a[i],i))ans++;
	printf("%lld\n",ans);
	return 0;
}