// 2024 IUSB Programming Competition
// Round 1 Problem 3
// Grid Count
// Solution by Liguo Yu

import java.util.Scanner;

public class round1_p3
{
    public static void main(String[] args)
    {
        Scanner input = new Scanner(System.in);
        int m = input.nextInt();
        int n = input.nextInt();
        int[][] array = new int[m][n];

        for (int i=0; i<m; i++)
        {
            for(int j=0; j<n; j++)
            {
                array[i][j] = input.nextInt();
            }
        }
        
        boolean[] result = new boolean[n];
        
        for(int j=0; j<n; j++)
        {
            result[j] = true;
        }
        
        for (int i=1; i<m; i++)
        {
            for(int j=0; j<n; j++)
            {
                if(array[i][j]<array[i-1][j])
                    result[j] = false;
            }
        }
        
        int count = 0;
        
        for(int j=0; j<n; j++)
        {
            if (result[j] == true)
                count = count + 1;
        }

        System.out.println(count);
    }
}