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.

Examples

Input

4
west
east
wait


Output

3


Input

9
different
different
different


Output

0


Input

7
zenkoku
touitsu
program


Output

13
#include<bits/stdc++.h>
using namespace std;
int n;
string a,b,c;
int cnt;
int main() {
	cin>>n>>a>>b>>c;
	cnt=2*n;
	for (int i=0;i<n;i++) {
		int k=0;
		if (a[i]==b[i]) k++;
		if (b[i]==c[i]) k++;
		if (a[i]==c[i]) k++;
		if (k==3) cnt-=2;
		if (k==1) cnt-=1;
	}
	cout<<cnt;
	return 0;
}