Buggy python submission (verdict: Time Limit Exceeded):
from collections import defaultdict,deque
from heapq import heappush, heappop
from itertools import permutations
import sys
import math
import bisect
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def I(): return int(sys.stdin.readline())
def LS():return [list(x) for x in sys.stdin.readline().split()]
def S():
    res = list(sys.stdin.readline())
    if res[-1] == "\n":
        return res[:-1]
    return res
def IR(n):
    return [I() for i in range(n)]
def LIR(n):
    return [LI() for i in range(n)]
def SR(n):
    return [S() for i in range(n)]
def LSR(n):
    return [LS() for i in range(n)]

sys.setrecursionlimit(1000000)
mod = 1000000007
"""
#N,K,Mが入力
    n,k,m=LI() 
    #N
    #x1 y1
    #.  .
    #xn ynが入力
    N=I()
    p=LIR(N)
    print(n,k,m,p)
"""
############################## ユニオン木(union tree) ###################################
#uf=UnionFind(n)と使う
# print(uf.roots())
# print(uf.all_group_members())
class UnionFind:
    def __init__(self, n):
        self.n=n
        self.par = [-1 for i in range(self.n+1)]
        self.rank = [0 for i in range(self.n+1)]#素集合でないとrankは意味がなさそう,素集合であればrank kには少なくとも2^k要素がある。
    
    # 検索
    def find(self, x):
        # if self.par[x] == x:
        if self.par[x] <0:
            return x
        else:
            self.par[x] = self.find(self.par[x])
            return self.par[x]

    # 併合
    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)
        if self.rank[x] < self.rank[y]:
            self.par[x] = y
        else:
            self.par[y] = x
            if self.rank[x] == self.rank[y]:
                self.rank[x] += 1
        
    # 同じ集合に属するか判定
    def same(self, x, y):
        return self.find(x) == self.find(y)

    #要素xが属するグループに属する要素をリストで返す
    def members(self, x):
        root = self.find(x)
        return [i for i in range(self.n+1) if self.find(i) == root]

    #すべての根の要素をリストで返す
    def roots(self):
        return [i for i, x in enumerate(self.par) if x<0]

    #グループの数を返す
    def group_count(self):
        return len(self.roots())

    #{ルート要素: [そのグループに含まれる要素のリスト], ...}の辞書を返す
    def all_group_members(self):
        return {int(r):self.members(r) for r in self.roots()}

    def __str__(self):
        return '\n'.join('{}: {}'.format(r, self.members(r)) for r in self.roots())

def resolve():
    n,m=LI()
    p=LI()
    x=LIR(m)

    uf=UnionFind(n)
    for i in range(m):
        uf.union(x[i][0],x[i][1])
    # print(uf.all_group_members())

    ans=0
    for i in range(n):
        if i+1==p[i]:
            ans+=1
        else:
            if uf.same(i+1,p[i]):
                ans+=1
    print(ans)

import sys
from io import StringIO
import unittest

class TestClass(unittest.TestCase):
    def assertIO(self, input, output):
        stdout, stdin = sys.stdout, sys.stdin
        sys.stdout, sys.stdin = StringIO(), StringIO(input)
        resolve()
        sys.stdout.seek(0)
        out = sys.stdout.read()[:-1]
        sys.stdout, sys.stdin = stdout, stdin
        self.assertEqual(out, output)
    def test_入力例_1(self):
        input = """5 2
5 3 1 4 2
1 3
5 4"""
        output = """2"""
        self.assertIO(input, output)
    def test_入力例_2(self):
        input = """3 2
3 2 1
1 2
2 3"""
        output = """3"""
        self.assertIO(input, output)
    def test_入力例_3(self):
        input = """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"""
        output = """8"""
        self.assertIO(input, output)
    def test_入力例_4(self):
        input = """5 1
1 2 3 4 5
1 5"""
        output = """5"""
        self.assertIO(input, output)

if __name__ == "__main__":
    # unittest.main()
    resolve()

Fixed submission:
from collections import defaultdict,deque
from heapq import heappush, heappop
from itertools import permutations
import sys
import math
import bisect
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def I(): return int(sys.stdin.readline())
def LS():return [list(x) for x in sys.stdin.readline().split()]
def S():
    res = list(sys.stdin.readline())
    if res[-1] == "\n":
        return res[:-1]
    return res
def IR(n):
    return [I() for i in range(n)]
def LIR(n):
    return [LI() for i in range(n)]
def SR(n):
    return [S() for i in range(n)]
def LSR(n):
    return [LS() for i in range(n)]

sys.setrecursionlimit(1000000)
mod = 1000000007
"""
#N,K,Mが入力
    n,k,m=LI() 
    #N
    #x1 y1
    #.  .
    #xn ynが入力
    N=I()
    p=LIR(N)
    print(n,k,m,p)
"""
############################## ユニオン木(union tree) ###################################
#uf=UnionFind(n)と使う
# print(uf.roots())
# print(uf.all_group_members())
class UnionFind:
    def __init__(self, n):
        self.n=n
        self.par = [-1 for i in range(self.n+1)]
        self.rank = [0 for i in range(self.n+1)]#素集合でないとrankは意味がなさそう,素集合であればrank kには少なくとも2^k要素がある。
    
    # 検索
    def find(self, x):
        # if self.par[x] == x:
        if self.par[x] <0:
            return x
        else:
            self.par[x] = self.find(self.par[x])
            return self.par[x]

    # 併合
    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)

        if x==y:
            return

        if self.rank[x] < self.rank[y]:
            self.par[x] = y
        else:
            self.par[y] = x
            if self.rank[x] == self.rank[y]:
                self.rank[x] += 1
        
    # 同じ集合に属するか判定
    def same(self, x, y):
        return self.find(x) == self.find(y)

    #要素xが属するグループに属する要素をリストで返す
    def members(self, x):
        root = self.find(x)
        return [i for i in range(self.n+1) if self.find(i) == root]

    #すべての根の要素をリストで返す
    def roots(self):
        return [i for i, x in enumerate(self.par) if x<0]

    #グループの数を返す
    def group_count(self):
        return len(self.roots())

    #{ルート要素: [そのグループに含まれる要素のリスト], ...}の辞書を返す
    def all_group_members(self):
        return {int(r):self.members(r) for r in self.roots()}

    def __str__(self):
        return '\n'.join('{}: {}'.format(r, self.members(r)) for r in self.roots())

def resolve():
    n,m=LI()
    p=LI()
    x=LIR(m)

    uf=UnionFind(n)
    for i in range(m):
        uf.union(x[i][0],x[i][1])
    # print(uf.all_group_members())

    ans=0
    for i in range(n):
        if i+1==p[i]:
            ans+=1
        else:
            if uf.same(i+1,p[i]):
                ans+=1
    print(ans)

import sys
from io import StringIO
import unittest

class TestClass(unittest.TestCase):
    def assertIO(self, input, output):
        stdout, stdin = sys.stdout, sys.stdin
        sys.stdout, sys.stdin = StringIO(), StringIO(input)
        resolve()
        sys.stdout.seek(0)
        out = sys.stdout.read()[:-1]
        sys.stdout, sys.stdin = stdout, stdin
        self.assertEqual(out, output)
    def test_入力例_1(self):
        input = """5 2
5 3 1 4 2
1 3
5 4"""
        output = """2"""
        self.assertIO(input, output)
    def test_入力例_2(self):
        input = """3 2
3 2 1
1 2
2 3"""
        output = """3"""
        self.assertIO(input, output)
    def test_入力例_3(self):
        input = """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"""
        output = """8"""
        self.assertIO(input, output)
    def test_入力例_4(self):
        input = """5 1
1 2 3 4 5
1 5"""
        output = """5"""
        self.assertIO(input, output)

if __name__ == "__main__":
    # unittest.main()
    resolve()