Buggy python submission (verdict: Runtime Error):
N, M = map(int,input().split())
P = list(map(int,input().split()))

class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

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

        if x == y:
            return

        if self.parents[x] > self.parents[y]:
            x, y = y, x

        self.parents[x] += self.parents[y]
        self.parents[y] = x
        
    def same(self, x, y):
        return self.find(x) == self.find(y)

    def members(self, x):
        root = self.find(x)
        return [i for i in range(self.n) if self.find(i) == root]

UFT = UnionFind(N)
for _ in range(M):
    x, y = map(int,input().split())
    UFT.union(x-1, y-1)

ans = 0

for i in range(N):
    if UTF.same(P[i] - 1, i):
        ans += 1
print(ans)

Fixed submission:
N, M = map(int,input().split())
P = list(map(int,input().split()))

class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

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

        if x == y:
            return

        if self.parents[x] > self.parents[y]:
            x, y = y, x

        self.parents[x] += self.parents[y]
        self.parents[y] = x
        
    def same(self, x, y):
        return self.find(x) == self.find(y)

    def members(self, x):
        root = self.find(x)
        return [i for i in range(self.n) if self.find(i) == root]

UFT = UnionFind(N)
for _ in range(M):
    x, y = map(int,input().split())
    UFT.union(x-1, y-1)

ans = 0

for i in range(N):
    if UFT.same(P[i] - 1, i):
        ans += 1
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
N, M = map(int,input().split())
P = list(map(int,input().split()))

class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

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

        if x == y:
            return

        if self.parents[x] > self.parents[y]:
            x, y = y, x

        self.parents[x] += self.parents[y]
        self.parents[y] = x

    def members(self, x):
        root = self.find(x)
        return [i for i in range(self.n) if self.find(i) == root]

UFT = UnionFind(N)
for _ in range(M):
    x, y = map(int,input().split())
    UFT.union(x-1, y-1)

ans = 0

for i in range(N):
    if P[i] - 1 in UFT.members(i):
        ans += 1
print(ans)

Fixed submission:
N, M = map(int,input().split())
P = list(map(int,input().split()))

class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

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

        if x == y:
            return

        if self.parents[x] > self.parents[y]:
            x, y = y, x

        self.parents[x] += self.parents[y]
        self.parents[y] = x
        
    def same(self, x, y):
        return self.find(x) == self.find(y)

    def members(self, x):
        root = self.find(x)
        return [i for i in range(self.n) if self.find(i) == root]

UFT = UnionFind(N)
for _ in range(M):
    x, y = map(int,input().split())
    UFT.union(x-1, y-1)

ans = 0

for i in range(N):
    if UFT.same(P[i] - 1, i):
        ans += 1
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
N, M = map(int,input().split())
P = list(map(int,input().split()))

class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

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

        if x == y:
            return

        if self.parents[x] > self.parents[y]:
            x, y = y, x

        self.parents[x] += self.parents[y]
        self.parents[y] = x

    def members(self, x):
        root = self.find(x)
        return [i for i in range(self.n) if self.find(i) == root]

UFT = UnionFind(N)
for _ in range(M):
    x, y = map(int,input().split())
    UFT.union(x-1, y-1)

ans = 0

for i in range(N):
    if P[i] - 1 in UFT.members(i):
        ans += 1
print(ans)

Fixed submission:
N, M = map(int,input().split())
P = list(map(int,input().split()))

class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

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

        if x == y:
            return

        if self.parents[x] > self.parents[y]:
            x, y = y, x

        self.parents[x] += self.parents[y]
        self.parents[y] = x
        
    def same(self, x, y):
        return self.find(x) == self.find(y)

    def members(self, x):
        root = self.find(x)
        return [i for i in range(self.n) if self.find(i) == root]

UFT = UnionFind(N)
for _ in range(M):
    x, y = map(int,input().split())
    UFT.union(x-1, y-1)

ans = 0

for i in range(N):
    if UFT.same(P[i] - 1, i):
        ans += 1
print(ans)