#include <bits/stdc++.h>
using namespace std;
const long long MOD = 1e9 + 7;
template <typename flow_t>
struct Dinic {
  const flow_t INF;
  struct edge {
    int to;
    flow_t cap;
    int rev;
    bool isrev;
    int idx;
  };
  vector<vector<edge> > graph;
  vector<int> min_cost, iter;
  Dinic(int V) : INF(numeric_limits<flow_t>::max()), graph(V) {}
  void add_edge(int from, int to, flow_t cap, int idx = -1) {
    edge a = {to, cap, (int)graph[to].size(), false, idx};
    graph[from].emplace_back(a);
    a = {from, 0, (int)graph[from].size() - 1, true, idx};
    graph[to].emplace_back(a);
  }
  bool bfs(int s, int t) {
    min_cost.assign(graph.size(), -1);
    queue<int> que;
    min_cost[s] = 0;
    que.push(s);
    while (!que.empty() && min_cost[t] == -1) {
      int p = que.front();
      que.pop();
      for (auto& e : graph[p]) {
        if (e.cap > 0 && min_cost[e.to] == -1) {
          min_cost[e.to] = min_cost[p] + 1;
          que.push(e.to);
        }
      }
    }
    return min_cost[t] != -1;
  }
  flow_t dfs(int idx, const int t, flow_t flow) {
    if (idx == t) return flow;
    for (int& i = iter[idx]; i < graph[idx].size(); i++) {
      edge& e = graph[idx][i];
      if (e.cap > 0 && min_cost[idx] < min_cost[e.to]) {
        flow_t d = dfs(e.to, t, min(flow, e.cap));
        if (d > 0) {
          e.cap -= d;
          graph[e.to][e.rev].cap += d;
          return d;
        }
      }
    }
    return 0;
  }
  flow_t max_flow(int s, int t) {
    flow_t flow = 0;
    while (bfs(s, t)) {
      iter.assign(graph.size(), 0);
      flow_t f = 0;
      while ((f = dfs(s, t, INF)) > 0) flow += f;
    }
    return flow;
  }
  void output() {
    for (int i = 0; i < graph.size(); i++) {
      for (auto& e : graph[i]) {
        if (e.isrev) continue;
        auto& rev_e = graph[e.to][e.rev];
        cout << i << "->" << e.to << " (flow: " << rev_e.cap << "/"
             << e.cap + rev_e.cap << ")" << endl;
      }
    }
  }
};
long long N, M;
vector<long long> L, R;
int main() {
  std::ios::sync_with_stdio(false);
  std::cin.tie(0);
  cin >> N >> M;
  L.resize(N);
  R.resize(N);
  for (long long n = 0; n < N; n++) {
    cin >> L[n] >> R[n];
  }
  Dinic<long long> D(N + M + 2);
  for (long long n = 1; n <= N; n++) {
    D.add_edge(0, n, 1);
  }
  for (long long n = 0; n < N; n++) {
    for (long long l = 1; l <= L[n]; l++) D.add_edge(n + 1, N + l, 1);
    for (long long r = R[n]; r <= M; r++) D.add_edge(n + 1, N + r, 1);
  }
  for (long long m = N + 1; m <= N + M; m++) {
    D.add_edge(m, N + M + 1, 1);
  }
  long long ans = D.max_flow(0, N + M + 1);
  cout << N - ans << "\n";
  return 0;
}
