Developers often face with regular expression patterns. A pattern is usually defined as a string consisting of characters and metacharacters that sets the rules for your search. These patterns are most often used to check whether a particular string meets the certain rules.

In this task, a pattern will be a string consisting of small English letters and question marks ('?'). The question mark in the pattern is a metacharacter that denotes an arbitrary small letter of the English alphabet. We will assume that a string matches the pattern if we can transform the string into the pattern by replacing the question marks by the appropriate characters. For example, string aba matches patterns: ???, ??a, a?a, aba.

Programmers that work for the R1 company love puzzling each other (and themselves) with riddles. One of them is as follows: you are given *n* patterns of the same length, you need to find a pattern that contains as few question marks as possible, and intersects with each of the given patterns. Two patterns intersect if there is a string that matches both the first and the second pattern. Can you solve this riddle?
The first line contains a single integer *n* (1 ≤ *n* ≤ 10<sup class="upper-index">5</sup>) — the number of patterns. Next *n* lines contain the patterns.

It is guaranteed that the patterns can only consist of small English letters and symbols '?'. All patterns are non-empty and have the same length. The total length of all the patterns does not exceed 10<sup class="upper-index">5</sup> characters.
n = int(input())
size = 0
vector = list(input())
size = len(vector)

if n == 1:
    for char in vector:
        if char == '?':
            print('a', end='')
        else:
            print(char, end='')

else:
    for idx in range(n-1):
        word = list(input())
        for idx1 in range(size):
            if vector[idx1] == '?':
                if word[idx1] == '?':
                    vector[idx1] = '.'
                else:
                    vector[idx1] = word[idx1]
            elif vector[idx1] == '.':
                if word[idx1] == '?':
                    vector[idx1] = '.'
                else:
                    vector[idx1] = word[idx1]
            elif vector[idx1] != word[idx1] and word[idx1] != '?':
                vector[idx1] = ','
    print(vector)

    for char in vector:
        if char == '.':
            print('a', end='')
        elif char == ',':
            print('?', end='')
        else:
            print(char, end='')

		 				 				 			  	   			  	 	