import java.util.*;

class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        int count = 0;
        
        int[][] figure = new int[n][2];
        figure[0][0] = sc.nextInt();
        figure[0][1] = sc.nextInt();
        
        for(int i=1;i<n;i++) {
            figure[i][0] = sc.nextInt();
            figure[i][1] = sc.nextInt();
            
            for(int j=1;j<=i;j--) {
                if(figure[i][0] < figure[i-j][0] && figure[i][1] > figure[i-j][0]) {
                    if(figure[i][0] > figure[i-j][1] && figure[i][1] < figure[i-j][1]) {
                        count++;
                    }
                } else if(figure[i][0] < figure[i-j][1] && figure[i][1] > figure[i-j][1]) {
                    if(figure[i][0] > figure[i-j][0] && figure[i][1] < figure[i-j][0]) {
                        count++;
                    }
                }
            }
        }
        
        
        System.out.println(count);
    }
}