#include <iostream>
#include <vector>
#include <cstdio>
#include <sstream>
#include <map>
#include <string>
#include <algorithm>
#include <queue>
#include <cmath>
#include <functional>
#include <set>
#include <ctime>
#include <random>
#include <chrono>
#include <cassert>
#include <tuple>
#include <utility>
using namespace std;

namespace {
  using Integer = long long; //__int128;
  template<class T, class S> istream& operator >> (istream& is, pair<T,S>& p){return is >> p.first >> p.second;}
  template<class T> istream& operator >> (istream& is, vector<T>& vec){for(T& val: vec) is >> val; return is;}
  template<class T> istream& operator ,  (istream& is, T& val){ return is >> val;}
  template<class T, class S> ostream& operator << (ostream& os, const pair<T,S>& p){return os << p.first << " " << p.second;}
  template<class T> ostream& operator << (ostream& os, const vector<T>& vec){for(size_t i=0; i<vec.size(); i++) os << vec[i] << (i==vec.size()-1?"":" "); return os;}
  template<class T> ostream& operator ,  (ostream& os, const T& val){ return os << " " << val;}

  template<class H> void print(const H& head){ cout << head; }
  template<class H, class ... T> void print(const H& head, const T& ... tail){ cout << head << " "; print(tail...); }
  template<class ... T> void println(const T& ... values){ print(values...); cout << endl; }

  template<class H> void eprint(const H& head){ cerr << head; }
  template<class H, class ... T> void eprint(const H& head, const T& ... tail){ cerr << head << " "; eprint(tail...); }
  template<class ... T> void eprintln(const T& ... values){ eprint(values...); cerr << endl; }

  class range{ Integer start_, end_, step_; public: struct range_iterator{ Integer val, step_; range_iterator(Integer v, Integer step) : val(v), step_(step) {} Integer operator * (){return val;} void operator ++ (){val += step_;} bool operator != (range_iterator& x){return step_ > 0 ? val < x.val : val > x.val;} }; range(Integer len) : start_(0), end_(len), step_(1) {} range(Integer start, Integer end) : start_(start), end_(end), step_(1) {} range(Integer start, Integer end, Integer step) : start_(start), end_(end), step_(step) {} range_iterator begin(){ return range_iterator(start_, step_); } range_iterator   end(){ return range_iterator(  end_, step_); } };

  inline string operator "" _s (const char* str, size_t size){ return move(string(str)); }
  constexpr Integer my_pow(Integer x, Integer k, Integer z=1){return k==0 ? z : k==1 ? z*x : (k&1) ? my_pow(x*x,k>>1,z*x) : my_pow(x*x,k>>1,z);}
  constexpr Integer my_pow_mod(Integer x, Integer k, Integer M, Integer z=1){return k==0 ? z%M : k==1 ? z*x%M : (k&1) ? my_pow_mod(x*x%M,k>>1,M,z*x%M) : my_pow_mod(x*x%M,k>>1,M,z);}
  constexpr unsigned long long operator "" _ten (unsigned long long value){ return my_pow(10,value); }

  inline int k_bit(Integer x, int k){return (x>>k)&1;} //0-indexed

  mt19937 mt(chrono::duration_cast<chrono::nanoseconds>(chrono::steady_clock::now().time_since_epoch()).count());

  template<class T> string join(const vector<T>& v, const string& sep){ stringstream ss; for(size_t i=0; i<v.size(); i++){ if(i>0) ss << sep; ss << v[i]; } return ss.str(); }

  inline string operator * (string s, int k){ string ret; while(k){ if(k&1) ret += s; s += s; k >>= 1; } return ret; }
}
constexpr long long mod = 9_ten + 7;

int sz;
class segTree{
 public:
  struct node {
    int min_val;
    int range_val;
  };
  node merge(node a, node b){
    int x = a.min_val + a.range_val;
    int y = b.min_val + b.range_val;
    return node{
      min(x,y),
      0
    };
  }


  vector<node> t;
  segTree(int n){
    sz = 1;
    while(sz<n) sz<<=1;
    t.resize(2*sz, node{114514893, 0});
  }

  node set(int val, int lb, int ub, int k=0, int l=0, int r=sz){
    if( r<=lb || ub<=l ) return t[k];
    if( lb<=l && r<=ub ){
      t[k].min_val = val;
      return t[k];
    }
    return t[k] = merge(
      set(val, lb, ub, k*2+1, l, (l+r)/2),
      set(val, lb, ub, k*2+2, (l+r)/2, r)
    );
  }
  void push(int k){
    for(int i=1; i<=2 && k*2+i < t.size(); i++ ){
      t[ k*2 + i ].range_val += t[k].range_val;
    }
    t[k].min_val += t[k].range_val;
    t[k].range_val = 0;
  }
  node add(int add_val, int lb, int ub, int k=0, int l=0, int r=sz){
    if( r<=lb || ub<=l ) return t[k];
    push(k);
    if( lb<=l && r<=ub ){
      t[k].range_val += add_val;
      return t[k];
    }

    return t[k] = merge(
      add(add_val, lb, ub, k*2+1, l, (l+r)/2),
      add(add_val, lb, ub, k*2+2, (l+r)/2, r)
    );
  }

  node get(int lb, int ub, int k=0, int l=0, int r=sz){
    if( r<=lb || ub<=l ) return node{114514893, 0};

    push(k);
    if( lb<=l && r<=ub ){
      return t[k];
    }

    return merge(
      add(lb, ub, k*2+1, l, (l+r)/2),
      add(lb, ub, k*2+2, (l+r)/2, r)
    );
  }
};

int main(){
  int n,m;
  cin >> n,m;

  vector<int> l(n), r(n);
  for(int i=0; i<n; i++){
    scanf("%d%d", &l[i], &r[i]);
  }

  vector<pair<int,int>> v(n);
  for(int i=0; i<n; i++){
    v[i] = {l[i], r[i]};
  }
  sort(v.begin(), v.end());

  segTree seg(m+10);
  for(int i=0; i<m; i++){
    seg.set(i+1, m-i, m-i+1);
  }
  seg.set(0, m+1, m+2);


  int ans = 0;
  int r_min = m+1;
  for(int i=0; i<n; i++){
    int ll,rr;
    tie(ll,rr) = v[i];
    seg.add(-1, 1, rr+1);

    auto x = seg.get(ll+1, m+2);
    int tmp = -min(0, ll+x.min_val);

    ans = max(tmp, ans);
    r_min = min(r_min, rr);
    if( r_min <= ll ){
      ans = max(n-m, ans);
    }
  }
  println(ans);

  return 0;
}


Measured memory_bytes: 7424