#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
using namespace std;

int main()
{
    int n, l;
    cin >> n >> l;
    int x1[n], x2[n];
    for(int i = 0; i < n; i++) {
        cin >> x1[i] >> x2[i];
    }
    int L = 0;
    int R = l;
    int zalepeni = 0;
    for(int i = 0; i < n; i++) {
        int a = x1[i];
        int b = x2[i];
        if(R < a) {
            continue;
        }
        if(b < L) {
            continue;
        }
        if(a < L and R < b) {
            continue;
        }
        if(L <= a and b <= R) {
            zalepeni += 1;
            continue;
        }
        if(a < L) {
            int strci = L - a;
            if(strci < 0) {
                strci *= -1; // dolzinata mora da e pozitiven broj
            }
            int dolzina = b - a;
            if(dolzina < 0) {
                dolzina *= -1;
            }
            if(strci <= dolzina / 2) {
                L = a;
                zalepeni += 1;
            }
        }
        else if(R < b) {
            int strci = b - R;
            if(strci < 0) {
                strci *= -1;
            }
            int dolzina = b - a;
            if(dolzina < 0) {
                dolzina *= -1;
            }
            if(strci <= dolzina / 2) {
                R = b;
                zalepeni += 1;
            }
        }
    }
    cout << zalepeni << endl;
    return 0;
}