Language: C++

#include <bits/stdc++.h>
 
//#include <unistd.h>
//#include <iostream>
 
using namespace std;
 
#define DEBUG(x) cerr<<#x<<": "<<x<<endl;
#define DEBUG_VEC(v) cerr<<#v<<":";for(int i=0;i<v.size();i++) cerr<<" "<<v[i]; cerr<<endl;
#define DEBUG_MAT(v) cerr<<#v<<endl;for(int i=0;i<v.size();i++){for(int j=0;j<v[i].size();j++) {cerr<<v[i][j]<<" ";}cerr<<endl;}
typedef long long ll;
#define int ll
 
#define vi vector<int>
#define vl vector<ll>
#define vii vector< vector<int> >
#define vll vector< vector<ll> >
#define vs vector<string>
#define pii pair<int,int>
#define pis pair<int,string>
#define psi pair<string,int>
#define pll pair<ll,ll>
template<class S, class T> pair<S, T> operator+(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first + t.first, s.second + t.second); }
template<class S, class T> pair<S, T> operator-(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first - t.first, s.second - t.second); }
template<class S, class T> ostream& operator<<(ostream& os, pair<S, T> p) { os << "(" << p.first << ", " << p.second << ")"; return os; }
#define X first
#define Y second
#define rep(i,n) for(int i=0;i<(n);i++)
#define rep1(i,n) for(int i=1;i<=(n);i++)
#define rrep(i,n) for(int i=(n)-1;i>=0;i--)
#define rrep1(i,n) for(int i=(n);i>0;i--)
#define REP(i,a,b) for(int i=a;i<b;i++)
#define in(x, a, b) (a <= x && x < b)
#define all(c) c.begin(),c.end()
template<class T> bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a = b; return 1; } return 0; }
#define UNIQUE(v) v.erase(std::unique(v.begin(), v.end()), v.end());
const ll inf = 1000000001;
const ll INF = (ll)1e18 + 1;
const long double pi = 3.1415926535897932384626433832795028841971L;
#define Sp(p) cout<<setprecision(25)<< fixed<<p<<endl;
int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
int dx2[8] = { 1,1,0,-1,-1,-1,0,1 }, dy2[8] = { 0,1,1,1,0,-1,-1,-1 };
#define fio() cin.tie(0); ios::sync_with_stdio(false);
const ll MOD = 1000000007;
//const ll MOD = 998244353;
// #define mp make_pair
//#define endl '\n'
 
int n, m;
vl memo;
int f(int mid, vector<pii> &lr) {
    if (memo[mid] != -1) return memo[mid];
    int idx = 0;
    priority_queue<int> pq;
    int res = 0;
    while (idx < n and lr[idx].first >= mid) {
        pq.push(lr[idx].second);
        idx++;
    }
    for (int i = mid - 1; i >= 0; i--) {
        while (idx < n and lr[idx].first >= i) {
            pq.push(lr[idx].second);
            idx++;
        }
        if (pq.size() > 0) {
            pq.pop();
            res++;
        }
    }
    while (idx < n) {
        pq.push(lr[idx].second);
        idx++;
    }

    for (int i = m - 1; i >= mid; i--) {
        while (pq.size() > 0) {
            int to = pq.top();
            pq.pop();
            if (to <= i) {
                res++;
                break;
            }
        }
        if (pq.size() == 0) break;
    }
    memo[mid] = res;
    return res;
}

signed main() {
    fio();
    cin >> n >> m;
    memo.resize(m + 2);
    fill(all(memo), -1);
    vector<pll> lr(n);
    rep (i, n) {
        cin >> lr[i].first >> lr[i].second;
        lr[i].first--; lr[i].second--;
    }
    auto cmp = [](pii a, pii b) {
        if (a.first != b.first) return a.first > b.first;
        else return a < b;
    };
    sort(all(lr), cmp);

    int ma = 0;
    rep (i, m + 1) {
        chmax(ma, f(i, lr));
    }
    cout << n - ma << endl;
    return 0;
    //DEBUG_VEC(lr);
    int l = 0, r = m;
    while (l + 2 < r) {
        int x1 = (2 * l + r) / 3, x2 = (l + 2 * r) / 3;
        int y1 = f(x1, lr), y2 = f(x2, lr);
        if (y1 == y2) {
            l = x1; r = x1;
            break;
        }
        if (y1 > y2) {
            r = x2;
        }
        else {
            l = x1;
        }
    }

    int ma = 0;
    for (int i = max(l - 1, 0LL); i <= min(r, m); i++) {
        chmax(ma, f(i, lr));
    }
    cout << n - ma << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:130:9: error: redeclaration of 'll ma'
  130 |     int ma = 0;
      |         ^~
a.cc:107:9: note: 'll ma' previously declared here
  107 |     int ma = 0;
      |         ^~