1032. 명령 프롬프트

import sys
input = sys.stdin.readline
n = int(input())
a =[]
for _ in range(n):
    a.append(input().strip())
for i in range(n):
    for j in range(len(a[0])):
      if a[i][j] == a[0][j]:
        pass
      else:
        a[0] = a[0][:j]+'?'+a[0][j+1:]
print(a[0])