Buggy python submission (verdict: Time Limit Exceeded):
import sys
input = sys.stdin.readline

N,K,L=map(int,input().split())
R=[list(map(int,input().split())) for i in range(K)]
T=[list(map(int,input().split())) for i in range(L)]

Group1=[i for i in range(N+1)]#グループ分け.Group[i]=jのときiとjは同じグループ
Group2=[i for i in range(N+1)]#グループ分け.Group[i]=jのときiとjは同じグループ

def find1(x):#find(a)=find(b)のとき同じグループ
    while Group1[x] != x:
        x=Group1[x]
    return x

def Union1(x,y):#xとyが同じグループになるよう更新
    if find1(x) != find1(y):
        Group1[find1(y)]=Group1[find1(x)]=min(find1(y),find1(x))

def find2(x):#find(a)=find(b)のとき同じグループ
    while Group2[x] != x:
        x=Group2[x]
    return x

def Union2(x,y):#xとyが同じグループになるよう更新
    if find2(x) != find2(y):
        Group2[find2(y)]=Group2[find2(x)]=min(find2(y),find2(x))

for i,j in R:
    Union1(i,j)

for i,j in T:
    Union2(i,j)

Grin1=[[] for i in range(N+1)]
Grin2=[[] for i in range(N+1)]

for i in range(1,N+1):
    Grin1[Group1[find1(i)]].append(i)
    Grin2[Group2[find2(i)]].append(i)

for i in range(1,N+1):
    Grin1[i]=set(Grin1[i])
    Grin2[i]=set(Grin2[i])

for i in range(1,N+1):
    print(len(Grin1[find1(i)] & Grin2[find2(i)]),end=" ")


Fixed submission:
import sys
input = sys.stdin.readline

N,K,L=map(int,input().split())
R=[list(map(int,input().split())) for i in range(K)]
T=[list(map(int,input().split())) for i in range(L)]

Group1=[i for i in range(N+1)]#グループ分け.Group[i]=jのときiとjは同じグループ
Group2=[i for i in range(N+1)]#グループ分け.Group[i]=jのときiとjは同じグループ

def find1(x):#find(a)=find(b)のとき同じグループ
    while Group1[x] != x:
        x=Group1[x]
    return x

def Union1(x,y):#xとyが同じグループになるよう更新
    if find1(x) != find1(y):
        Group1[find1(y)]=Group1[find1(x)]=min(find1(y),find1(x))

def find2(x):#find(a)=find(b)のとき同じグループ
    while Group2[x] != x:
        x=Group2[x]
    return x

def Union2(x,y):#xとyが同じグループになるよう更新
    if find2(x) != find2(y):
        Group2[find2(y)]=Group2[find2(x)]=min(find2(y),find2(x))

for i,j in R:
    Union1(i,j)

for i,j in T:
    Union2(i,j)

from collections import defaultdict
ANS = defaultdict(int)

for i in range(1,N+1):
    ANS[(find1(i),find2(i))]+=1

for i in range(1,N+1):
    print(ANS[(find1(i),find2(i))])

Buggy python submission (verdict: Time Limit Exceeded):
N,K,L=map(int,input().split())
R=[list(map(int,input().split())) for i in range(K)]
T=[list(map(int,input().split())) for i in range(L)]

Group1=[i for i in range(N+1)]#グループ分け.Group[i]=jのときiとjは同じグループ
Group2=[i for i in range(N+1)]#グループ分け.Group[i]=jのときiとjは同じグループ

def find1(x):#find(a)=find(b)のとき同じグループ
    while Group1[x] != x:
        x=Group1[x]
    return x

def Union1(x,y):#xとyが同じグループになるよう更新
    if find1(x) != find1(y):
        Group1[find1(y)]=Group1[find1(x)]=min(find1(y),find1(x))

def find2(x):#find(a)=find(b)のとき同じグループ
    while Group2[x] != x:
        x=Group2[x]
    return x

def Union2(x,y):#xとyが同じグループになるよう更新
    if find2(x) != find2(y):
        Group2[find2(y)]=Group2[find2(x)]=min(find2(y),find2(x))

for i,j in R:
    Union1(i,j)

for i,j in T:
    Union2(i,j)

Grin1=[set() for i in range(N+1)]
Grin2=[set() for i in range(N+1)]

for i in range(1,N+1):
    Grin1[Group1[find1(i)]].add(i)
    Grin2[Group2[find2(i)]].add(i)

for i in range(1,N+1):
    print(len(Grin1[find1(i)] & Grin2[find2(i)]),end=" ")


Fixed submission:
import sys
input = sys.stdin.readline

N,K,L=map(int,input().split())
R=[list(map(int,input().split())) for i in range(K)]
T=[list(map(int,input().split())) for i in range(L)]

Group1=[i for i in range(N+1)]#グループ分け.Group[i]=jのときiとjは同じグループ
Group2=[i for i in range(N+1)]#グループ分け.Group[i]=jのときiとjは同じグループ

def find1(x):#find(a)=find(b)のとき同じグループ
    while Group1[x] != x:
        x=Group1[x]
    return x

def Union1(x,y):#xとyが同じグループになるよう更新
    if find1(x) != find1(y):
        Group1[find1(y)]=Group1[find1(x)]=min(find1(y),find1(x))

def find2(x):#find(a)=find(b)のとき同じグループ
    while Group2[x] != x:
        x=Group2[x]
    return x

def Union2(x,y):#xとyが同じグループになるよう更新
    if find2(x) != find2(y):
        Group2[find2(y)]=Group2[find2(x)]=min(find2(y),find2(x))

for i,j in R:
    Union1(i,j)

for i,j in T:
    Union2(i,j)

from collections import defaultdict
ANS = defaultdict(int)

for i in range(1,N+1):
    ANS[(find1(i),find2(i))]+=1

for i in range(1,N+1):
    print(ANS[(find1(i),find2(i))])