#include<bits/stdc++.h>
using namespace std;
#define int long long
int ans = 0, more = 0, less_ = 0;

struct event{
    int l, r, type, now_;
    event(){}
    event(int a, int b, int c, int d){
        l = a; r = b; type = c, now_ = d;
    }
};

bool cmp(event a, event b){
    //if( ((a.type == 0) ? a.l : a.r) == ((b.type == 0) ? b.l : b.r)) return (a.type < b.type);
    //return (((a.type == 0) ? a.l : a.r) < ((b.type == 0) ? b.l : b.r));
    if(a.now_ == b.now_) return (a.type < b.type);
    return(a.now_ < b.now_);
}

void upd(){
    if(less_ - more > ans) ans = less_ - more;
}

signed main(){
    int n, t;
    cin >> n >> t;
    --t;
    vector<event> s;
    int a, b;
    for(int i = 0; i < n; ++i){
        cin >> a >> b;
        --a;
        s.push_back(event(a + 1, b, 0, a + 1));
        s.push_back(event(a + 1, b, 1, b));
    }
    sort(s.begin(), s.end(), cmp);
   // cout << s.size() << '\n';
   // for(auto i: s) cout << "<" << i.l << ", " << i.r << ", " << i.now_ << "> ";
    int start = 0, finish = 0, i2 = 0;
    //event q1, q2;
    for(start; start < s.size(); ++start){
        if(start > 0){
            if(start - 1 == finish && start < s.size()){
                ++finish;
                if(s[finish].type) more = max((long long)(0), more - 1);
                upd();
            }
           // q1 = s[finish], q2 = s[start - 1];
            if(s[start - 1].type == 0){
            if(s[finish].now_ <= s[start - 1].r) ++more;
            else max((long long)(0), less_ - 1);
            upd();
            }
        }
        upd();
       // cout << start << ' ' << finish << ' ' << less_ << ' ' << more << ' ' << ans << '\n';
       // q1 = s[finish + 1], q2 = s[start];
        while(finish < s.size() - 1 && s[finish + 1].now_ - s[start].now_ <= t) {
            ++finish;
         //   q1 = s[finish];
            if(s[finish].type == 1){
                if(s[start].now_ <= s[finish].l) ++less_;
                else max((long long)(0), more - 1);
                upd();
            }
          //  cout << "   " << start << ' ' << finish << ' ' << ((q2.type == 0) ? q2.l : q2.l ) << ' ' << ((s[finish + 1].type == 0) ? s[finish + 1].l : s[finish + 1].l) << '\n';
        }
        upd();
       // cout << start << ' ' << finish << ' ' << less_ << ' ' << more << ' ' << ans << '\n';
    }
    cout << ans;
    return 0;
}