set1=set(input().split())#TAKING INPUT OF SETS
set2=set(input().split())
l=[]#CREATING EMPTY LIST FOR STORING THE COMMON DATA OF SETS
flag=0
#LOOP FOR CHECKING COMMON VALUE IN SETS 
for i in set1:
    for j in set2:
        if i==j:
            flag=1
            l.append(i)
if flag==0:#CHECKING FLAG VALUE IF IT IS ZERO THEN IT MEANS THERE IS NO COMMON DATA
    print("NULL")
l1=[]#LIST FOR STORING ALPHABATIC DATA
l2=[]#LIST FOR STORING NUMERIC DATA
#SEPARATING ALPHABATIC AND NUMERIC DATA
for i in l:
    i=str(i)
    if i.isalpha():
        l1.append(i)
    elif i.isdigit():
        l2.append(i)
l1=sorted(l1)#SORTING ALPHABATIC DATA
l2=sorted(l2)#SORTING NUMERIC DATA
s=''
#STORING THE ALPHABATIC AND NUMERIC DATA IN SINGLE VARIABLE
for i in l1:
    s=s+i
for j in l2:
    s=s+j
print(' '.join(s))#JOINING ALPHABATIC AND NUMERIC DATA