import java.io.*;
import java.util.*;

public class Solution {

    public static void main(String[] args) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
        
        Scanner scan = new Scanner(System.in);
		int[][] square = new int[3][3];
		for(int i =0; i < 3; i++){
			for(int j =0; j < 3; j++){
			square[i][j] = scan.nextInt();
			}
		}
		scan.close();
	
		int row = -1;
		int col = -1;
		
		for(int i =0; i < 3; i++){
			int sum = 0;
			for(int j =0; j < 3; j++){
				sum += square[i][j];
			}
			if(sum != 15){
				row = i;
				break;
			}
		}
		
		for (int j =0 ; j < 3; j++){
			int sum = 0;
			for (int i = 0; i < 3 ; i ++){
				sum+= square[i][j];
			}
			if(sum != 15){
				col = j;
				break;
			}
		}
		
		int cell = square[row][col];
		int sum = 0;
		for(int i = 0 ; i < 3; i++){
			sum+= square[row][i];
		}
		int diff = 15 - sum;
		System.out.println(diff);
        
    }
}