Shared code

//#pragma GCC optimize("Ofast")
// #pragma GCC target("avx,avx2,fma")

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

#define fastio()                     \
   ios_base::sync_with_stdio(false); \
   cin.tie(NULL);                    \
   cout.tie(NULL)
#define endl         '\n'
#define all(x)       (x).begin(), (x).end() //greater<int>()
#define ll           long long
#define PB           push_back
#define MP           make_pair
#define ff           first
#define ss           second
#define in           insert
#define lb           lower_bound
#define ub           upper_bound
#define sz(x)        (int)(x).size()
#define YES          cout << "YES" << endl
#define NO           cout << "NO" << endl
#define fr(n)        for (int i = 0; i < n; i++)
#define fr1(n)       for (int i = 1; i <= n; i++)
#define frj(n)       for (int j = 0; j < n; j++)
#define frj1(n)      for (int j = 1; j <= n; j++)
#define fi(a, b, v)  for (int i = (a); i <= (b); i += v)
#define fj(a, b, v)  for (int j = (a); j <= (b); j += v)
#define fir(a, b, v) for (int i = (a); i >= (b); i -= v)
#define fjr(a, b, v) for (int j = (a); j >= (b); j -= v)
#define trav(v)      for (auto x : v)
#define LCM(a, b)    (a / __gcd(a, b)) * b
#define GCD(a, b)    __gcd(a, b)
#define UNIQUE(a)    sort(all(a)), a.erase(unique(all(a)), a.end())
#define clock_start  auto time_req = clock()
#define clock_stop   cerr << "\nSolved, time = " << (float)(clock() - time_req) / CLOCKS_PER_SEC << "s\n"
#define testcase \
   int t;        \
   cin >> t;     \
   while (t--)

typedef pair<int, int> PI;
typedef vector<int> VI;
typedef vector<ll> VLL;
typedef vector<string> VS;
typedef vector<PI> VII;
typedef unsigned long long ull;
typedef long double lld;

template <typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

const ll mod = 1000000007;
const int N = 1e3 + 5;

int main()
{
   clock_start;
#ifndef ONLINE_JUDGE
   freopen("input.txt", "r", stdin);
   freopen("output.txt", "w", stdout);
   freopen("error.txt", "w", stderr);
#endif
   fastio();
   int n, k, c = 0;
   cin >> n >> k;
   int tk = k;
   VII ar(n);
   fr(n)
   {
      cin >> ar[i].ss;
      cin >> ar[i].ff;
   }
   sort(all(ar));
   // debug(ar);
   queue<int> q;
   fr(n)
   {
      if (!q.empty() && q.front() <= ar[i].ss)
      {
         // cout << "pop ->" << q.front() << " " << i << endl;
         q.pop();
         tk++;
      }
      if (tk > 0)
      {
         c++;
         tk--;
         // cout << "push ->" << ar[i].ff << endl;
         q.push(ar[i].ff);
      }
      // cout << tk << endl;
   }
   cout << c << endl;
   clock_stop;
   return 0;
}