Problem:
There are N cities. There are also K roads and L railways, extending between the cities. The i-th road bidirectionally connects the p_i-th and q_i-th cities, and the i-th railway bidirectionally connects the r_i-th and s_i-th cities. No two roads connect the same pair of cities. Similarly, no two railways connect the same pair of cities.  We will say city A and B are _connected by roads_ if city B is reachable from city A by traversing some number of roads. Here, any city is considered to be connected to itself by roads. We will also define _connectivity by railways_ similarly.  For each city, find the number of the cities connected to that city by both roads and railways.

Incorrect submission (verdict: Wrong Answer):
import sys
from collections import deque
from collections import defaultdict
from collections import Counter

def conn(n,m,e):
    d=dict(zip(range(1,n+1),range(1,n+1)))
    c=0
    for edge in e:
        a=edge[0]
        b=edge[1]
        da=d[a]
        db=d[b]
        if da==m and db==m:
            d[a]=c
            d[b]=c
            c+=1
        else:
            d[a]=min(da,db)
            d[b]=min(da,db)
    return d.values()

def main(n,k,l,e1,e2):
    d1=conn(n,k,e1)
    d2=conn(n,l,e2)
    p=tuple(zip(iter(d1),iter(d2)))
    print(p)
    d=Counter(p)
    print(d)
    d[(k,l)]=1
    print(' '.join([str(d[x]) for x in p]))

if __name__=='__main__':
    ssr=sys.stdin.readline
    n,k,l=map(int,ssr().strip().split())
    e1=[]
    e2=[]
    for _ in range(k):
        e1.append(tuple(map(int,ssr().strip().split())))
    for _ in range(l):
        e2.append(tuple(map(int,ssr().strip().split())))
    main(n,k,l,e1,e2)


Fixed, accepted submission:
import sys
from collections import deque
from collections import defaultdict
from collections import Counter

def conn(n,m,e):
    d=dict(zip(range(1,n+1),range(-1,(-1)*n-1,-1)))
    td=defaultdict(lambda:deque([])) 
    c=1
    for edge in e:
        a=edge[0]
        b=edge[1]
        da=d[a] 
        db=d[b]
        if da<0 and db<0:
            d[a]=c
            d[b]=c
            td[c].append(a)
            td[c].append(b)
            c+=1
        elif da>0 and db<0:
            d[b]=da
            td[d[a]].append(b)
        elif da<0 and db>0:
            d[a]=db
            td[d[b]].append(a)
        elif da>0 and db>0 and da!=db:
            for x in td[db]:
                d[x]=da
                td[da].append(x)

    return list(d.values())


#     ed=defaultdict(lambda:deque())
#     for edge in e:
#         ed[edge[0]].append(edge[1])
#     c=0
#     s=[0]*n
#     label=[0]*n

#         if s[i-1]==0:
#             c+=1
#             label[c-1]=c
#             stack=deque([i])
#             while stack:
#                 w=stack.pop()
#                 s[w-1]=c
#                 while ed[w]:
#                     wn=ed[w].pop()
#                     if s[wn-1]==0:
#                         s[wn-1]=c
#                         if ed[wn]:
#                             stack.append(w)
#                             w=wn
#                     elif s[wn-1]<c:
#                         label[s[wn-1]-1]=c
#     print(s)
#     print(label)

           
def components(n,k,e):
    ed=defaultdict(lambda:deque())
    for edge in e:
        ed[edge[0]].append(edge[1])
        ed[edge[1]].append(edge[0])
    c=0
    s=[0]*n
    stack=deque()
    for i in range(1,n+1):
        if s[i-1]==0:
            c+=1
            stack.clear()
            stack.append(i)
            while stack:
                w=stack.pop()
                s[w-1]=c
                while ed[w]:
                    wn=ed[w].pop()
                    if s[wn-1]==0:
                        s[wn-1]=c
                        if ed[wn]:
                            stack.append(w)
                            w=wn
    return [s[i] for i in range(n)] 

def components2(n,k,e):
    es=deque(set((edge[0],edge[1])) for edge in e)
    c=0
    s=deque()
    stack=deque()
    while es:
        f=es.pop()
        stack.clear()
        while es:
            l=len(es)
            g=es.pop()
            if g&f:
                f|=g
            else:
                stack.append(g)
            if l==len(stack):
                s.append(f)
                break
            es=stack
    t=[0]*n
    c=0
    while s:
        for x in s.pop():
            t[x-1]=c
        c+=1
    return t
                
                
        
        
def main(n,k,l,e1,e2):
    d1=components(n,k,e1)
    d2=components(n,l,e2)
    p=tuple(zip(iter(d1),iter(d2)))
    d=Counter(p)
    # print(d1,d2,d,p)
    print(' '.join([str(d[x]) for x in p])) 

if __name__=='__main__':
    ssr=sys.stdin.readline
    n,k,l=map(int,ssr().strip().split())
    e1=[]
    e2=[]
    for _ in range(k):
        e1.append(tuple(map(int,ssr().strip().split())))
    for _ in range(l):
        e2.append(tuple(map(int,ssr().strip().split())))
    main(n,k,l,e1,e2)