passw1 = str(input())
passw2 = str(input())
passw3 = str(input())
result = ''
for l in range(len(passw1)):
l1, l2, l3 = passw1[l], passw2[l], passw3[l]
l_string = l1+l2+l3
repeated_letters = [letter for letter in l_string if l_string. count(letter)>1]
if len(repeated_letters) == 0:
result += '*'
elif len(repeated_letters) == 2:
letter = repeated_letters[0]
if letter == '*':
result += l_string. replace('*', '')
else:
result += letter
else:
result += repeated_letters[0]
print(result)