// iostream is too mainstream
#include <cstdio>
// bitch please
#include <iostream>
#include <vector>
#include <set>
#include <map>
#include <string>
#include <queue>
#include <stack>
#include <algorithm>
#include <iomanip>
#define dibs reserve
#define OVER9000 1234567890
#define patkan 9
#define tisic 47
#define soclose 10e-7
#define ALL_THE(CAKE,LIE) for(auto LIE =CAKE.begin(); LIE != CAKE.end(); LIE++)
#define chocolate win
#define ff first
#define ss second
#define abs(x) ((x < 0)?-(x):(x))
// mylittlepony
using namespace std;
int main() {
cin.sync_with_stdio(0);
int N;
cin >> N;
string a[3];
cin >> a[0] >> a[1] >> a[2];
for(int i =0; i < N; i++) {
if(a[0][i] == a[1][i]) {cout << a[0][i]; continue;}
if(a[1][i] == a[2][i]) {cout << a[1][i]; continue;}
cout << a[0][i];}
cout << "\n";
return 0;}
// look at my code
// my code is amazing
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