Buggy python submission (verdict: Time Limit Exceeded):
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 size(self, x):
        return -self.parents[self.find(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]

    def roots(self):
        return [i for i, x in enumerate(self.parents) if x < 0]

    def group_count(self):
        return len(self.roots())

    def all_group_members(self):
        return {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())
      
n,m=map(int,input().split())
p = [int(i)-1 for i in input().split() ]

uf = UnionFind(n)
for i in range(m):
    x,y = map(int,input().split())
    uf.union(x-1,y-1)

ans=0
groups = uf.all_group_members().values()

for c in groups:
    ans+= len( set(c) & set(p[i] for i in c ) ) 
print(ans)
      


Fixed submission:
n,m=map(int,input().split())
p = [int(i)-1 for i in input().split() ]


tree=[[] for _ in range(n)]
for i in range(m):
    a,b = map(int,input().split())
    tree[a-1].append(b-1)
    tree[b-1].append(a-1)

from collections import deque

groups=[]
been=[0]*n
for i in range(n):
    if been[i]==0:
        group=[i]
        been[i]=1
        q = deque([(i,togo) for togo in tree[i]]) 
        while q:
            parent,x = q.popleft()
            if been[x]==1:
                continue
            been[x]=1
            group.append(x)
            for y in tree[x]:
                if y == parent:#親ノードを飛ばし
                    continue
                q.append((x,y))#子ノードを追加
        groups.append(group)

ans=0
for group in groups:
    ans+= len( set(group) & set(p[g] for g in group) )

print(ans)

Buggy python submission (verdict: Runtime Error):
n,m=map(int,input().split())
p = [int(i)-1 for i in input().split() ]

uf = UnionFind(n)
for i in range(m):
    x,y = map(int,input().split())
    uf.union(x-1,y-1)

ans=0
groups = uf.all_group_members().values()

for c in groups:
    ans+= len( set(c) & set(p[i] for i in c ) ) 
print(ans)

Fixed submission:
n,m=map(int,input().split())
p = [int(i)-1 for i in input().split() ]


tree=[[] for _ in range(n)]
for i in range(m):
    a,b = map(int,input().split())
    tree[a-1].append(b-1)
    tree[b-1].append(a-1)

from collections import deque

groups=[]
been=[0]*n
for i in range(n):
    if been[i]==0:
        group=[i]
        been[i]=1
        q = deque([(i,togo) for togo in tree[i]]) 
        while q:
            parent,x = q.popleft()
            if been[x]==1:
                continue
            been[x]=1
            group.append(x)
            for y in tree[x]:
                if y == parent:#親ノードを飛ばし
                    continue
                q.append((x,y))#子ノードを追加
        groups.append(group)

ans=0
for group in groups:
    ans+= len( set(group) & set(p[g] for g in group) )

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
import sys
input = sys.stdin.readline
def main():
    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]
    
        def roots(self):
            return [i for i, x in enumerate(self.parents) if x < 0]
        
        def all_group_members(self):
            return {r: self.members(r) for r in self.roots()}
    
          
    uf = UnionFind(n)
    for i in range(m):
        x,y = map(int,input().split())
        uf.union(x-1,y-1)
    
    ans=0
    groups = uf.all_group_members().values()
    for cand in groups:
        ans+=len(set(cand) & set(p[i]-1 for i in cand) )
    print(ans)
    
main()

Fixed submission:
n,m=map(int,input().split())
p = [int(i)-1 for i in input().split() ]


tree=[[] for _ in range(n)]
for i in range(m):
    a,b = map(int,input().split())
    tree[a-1].append(b-1)
    tree[b-1].append(a-1)

from collections import deque

groups=[]
been=[0]*n
for i in range(n):
    if been[i]==0:
        group=[i]
        been[i]=1
        q = deque([(i,togo) for togo in tree[i]]) 
        while q:
            parent,x = q.popleft()
            if been[x]==1:
                continue
            been[x]=1
            group.append(x)
            for y in tree[x]:
                if y == parent:#親ノードを飛ばし
                    continue
                q.append((x,y))#子ノードを追加
        groups.append(group)

ans=0
for group in groups:
    ans+= len( set(group) & set(p[g] for g in group) )

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
import sys
input = sys.stdin.readline
def main():
    n,m=map(int,input().split())
    p = [int(i)-1 for i in 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 size(self, x):
            return -self.parents[self.find(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]
    
        def roots(self):
            return [i for i, x in enumerate(self.parents) if x < 0]
    
        def group_count(self):
            return len(self.roots())
    
        def all_group_members(self):
            return {r: self.members(r) for r in self.roots()}
    
          
    uf = UnionFind(n)
    for i in range(m):
        x,y = map(int,input().split())
        uf.union(x-1,y-1)
    
    ans=0
    groups = uf.all_group_members().values()
    for cand in groups:
        ans+=len(set(cand) & set(p[i] for i in cand) )
    print(ans)
    
main()

Fixed submission:
n,m=map(int,input().split())
p = [int(i)-1 for i in input().split() ]


tree=[[] for _ in range(n)]
for i in range(m):
    a,b = map(int,input().split())
    tree[a-1].append(b-1)
    tree[b-1].append(a-1)

from collections import deque

groups=[]
been=[0]*n
for i in range(n):
    if been[i]==0:
        group=[i]
        been[i]=1
        q = deque([(i,togo) for togo in tree[i]]) 
        while q:
            parent,x = q.popleft()
            if been[x]==1:
                continue
            been[x]=1
            group.append(x)
            for y in tree[x]:
                if y == parent:#親ノードを飛ばし
                    continue
                q.append((x,y))#子ノードを追加
        groups.append(group)

ans=0
for group in groups:
    ans+= len( set(group) & set(p[g] for g in group) )

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
def main():
    n,m=map(int,input().split())
    p = [int(i)-1 for i in 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 size(self, x):
            return -self.parents[self.find(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]
    
        def roots(self):
            return [i for i, x in enumerate(self.parents) if x < 0]
    
        def group_count(self):
            return len(self.roots())
    
        def all_group_members(self):
            return {r: self.members(r) for r in self.roots()}
    
          
    uf = UnionFind(n)
    for i in range(m):
        x,y = map(int,input().split())
        uf.union(x-1,y-1)
    
    ans=0
    groups = uf.all_group_members().values()
    for cand in groups:
        ans+=len(set(cand) & set(p[i] for i in cand) )
    print(ans)
    
main()

Fixed submission:
n,m=map(int,input().split())
p = [int(i)-1 for i in input().split() ]


tree=[[] for _ in range(n)]
for i in range(m):
    a,b = map(int,input().split())
    tree[a-1].append(b-1)
    tree[b-1].append(a-1)

from collections import deque

groups=[]
been=[0]*n
for i in range(n):
    if been[i]==0:
        group=[i]
        been[i]=1
        q = deque([(i,togo) for togo in tree[i]]) 
        while q:
            parent,x = q.popleft()
            if been[x]==1:
                continue
            been[x]=1
            group.append(x)
            for y in tree[x]:
                if y == parent:#親ノードを飛ばし
                    continue
                q.append((x,y))#子ノードを追加
        groups.append(group)

ans=0
for group in groups:
    ans+= len( set(group) & set(p[g] for g in group) )

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
n,m=map(int,input().split())
p = [int(i)-1 for i in 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 size(self, x):
        return -self.parents[self.find(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]

    def roots(self):
        return [i for i, x in enumerate(self.parents) if x < 0]

    def group_count(self):
        return len(self.roots())

    def all_group_members(self):
        return {r: self.members(r) for r in self.roots()}

      
uf = UnionFind(n)
for i in range(m):
    x,y = map(int,input().split())
    uf.union(x-1,y-1)

ans=0
groups = uf.all_group_members().values()
for cand in groups:
    ans+=len(set(cand) & set(p[i] for i in cand) )
print(ans)

Fixed submission:
n,m=map(int,input().split())
p = [int(i)-1 for i in input().split() ]


tree=[[] for _ in range(n)]
for i in range(m):
    a,b = map(int,input().split())
    tree[a-1].append(b-1)
    tree[b-1].append(a-1)

from collections import deque

groups=[]
been=[0]*n
for i in range(n):
    if been[i]==0:
        group=[i]
        been[i]=1
        q = deque([(i,togo) for togo in tree[i]]) 
        while q:
            parent,x = q.popleft()
            if been[x]==1:
                continue
            been[x]=1
            group.append(x)
            for y in tree[x]:
                if y == parent:#親ノードを飛ばし
                    continue
                q.append((x,y))#子ノードを追加
        groups.append(group)

ans=0
for group in groups:
    ans+= len( set(group) & set(p[g] for g in group) )

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
n,m=map(int,input().split())
p = [int(i)-1 for i in 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 size(self, x):
        return -self.parents[self.find(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]

    def roots(self):
        return [i for i, x in enumerate(self.parents) if x < 0]

    def group_count(self):
        return len(self.roots())

    def all_group_members(self):
        return {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())



uf = UnionFind(n)
for i in range(m):
    x,y = map(int,input().split())
    uf.union(x-1,y-1)

ans=0
for cand in uf.all_group_members().values():
    ans+=len(set(cand) & set(p[i] for i in cand) )
print(ans)

Fixed submission:
n,m=map(int,input().split())
p = [int(i)-1 for i in input().split() ]


tree=[[] for _ in range(n)]
for i in range(m):
    a,b = map(int,input().split())
    tree[a-1].append(b-1)
    tree[b-1].append(a-1)

from collections import deque

groups=[]
been=[0]*n
for i in range(n):
    if been[i]==0:
        group=[i]
        been[i]=1
        q = deque([(i,togo) for togo in tree[i]]) 
        while q:
            parent,x = q.popleft()
            if been[x]==1:
                continue
            been[x]=1
            group.append(x)
            for y in tree[x]:
                if y == parent:#親ノードを飛ばし
                    continue
                q.append((x,y))#子ノードを追加
        groups.append(group)

ans=0
for group in groups:
    ans+= len( set(group) & set(p[g] for g in group) )

print(ans)