Untitled

#include <iostream>
#include "windows.h"
#include <iostream>
using namespace std;
int main() {
	string b,c;
	int a;
	cin >> a;
	cin >> b;
	c = b;
	for (int i = 0; i < a-1; i++){
		cin >> b;
		for (int i = 0; i < a; i++){
			if (c[i] == '_') {
				c[i] = b[i];
			}
		}
		
	}
	cout << c;
}