Problem:
Score : 200 points

Problem Statement

You are given three strings A, B and C. Each of these is a string of length N consisting of lowercase English letters.

Our objective is to make all these three strings equal. For that, you can repeatedly perform the following operation:

Operation: Choose one of the strings A, B and C, and specify an integer i between 1 and N (inclusive). Change the i-th character from the beginning of the chosen string to some other lowercase English letter.

What is the minimum number of operations required to achieve the objective?

Constraints

1 \leq N \leq 100

Each of the strings A, B and C is a string of length N.

Each character in each of the strings A, B and C is a lowercase English letter.

Input

Input is given from Standard Input in the following format:

N
A
B
C

Output

Print the minimum number of operations required.

Sample Input 1

4
west
east
wait

Sample Output 1

3

In this sample, initially A = west、B = east、C = wait. We can achieve the objective in the minimum number of operations by performing three operations as follows:

Change the second character in A to a. A is now wast.

Change the first character in B to w. B is now wast.

Change the third character in C to s. C is now wast.

Sample Input 2

9
different
different
different

Sample Output 2

0

If A, B and C are already equal in the beginning, the number of operations required is 0.

Sample Input 3

7
zenkoku
touitsu
program

Sample Output 3

13

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.io.*;
import java.util.Scanner;
import java.util.List;
import java.util.ArrayList;
import java.util.List;
 
public class Main{
 
     public static void main(String[] args){
        
        try{
        Scanner scan = new Scanner(System.in);
        
        List<String> inputs = new ArrayList<String>();
        
        while(scan.hasNextLine()){
            
            inputs.add(scan.next());
            
        }
            //格納(N A B C)
            int n = Integer.parseInt(inputs.get(0));
            String a = inputs.get(1);
            String b = inputs.get(2);
            String c = inputs.get(3);
            
            int count = 0;
            
            for(int i = 0; i < n; i++){
                
            String ta =String.valueOf(a.charAt(i));
            String tb = String.valueOf(b.charAt(i));
            String tc = String.valueOf(c.charAt(i));

            boolean ab = ta.equals(tb);
            boolean bc = tb.equals(tc);
            boolean ca = tc.equals(ta);
            
            if(!ab && !bc && !ca){
                
                count = count + 2;
                        
            }else if(ab && bc && ca){
        
                count = count;
            
            }else{
                count = count + 1;
            }
            
            }
            System.out.println(count);
            
        
         }catch(Exception e){
        
           System.out.println(e); 
           
         }
     }
}