#include <bits/stdc++.h>
using namespace std;
struct edge {
  int to, cap, rev;
  edge() {}
  edge(int to, int cap, int rev) : to(to), cap(cap), rev(rev) {}
};
vector<edge> G[800800];
map<int, int> M[800800];
int level[800800];
int iter[800800];
void add_edge(int from, int to, int cap) {
  M[from][to] = G[from].size();
  M[to][from] = G[to].size();
  G[from].push_back(edge(to, cap, G[to].size()));
  G[to].push_back(edge(from, 0, G[from].size() - 1));
}
void bfs(int s) {
  memset(level, -1, sizeof(level));
  queue<int> que;
  level[s] = 0;
  que.push(s);
  while (!que.empty()) {
    int v = que.front();
    que.pop();
    for (int i = 0; i < (int)G[v].size(); i++) {
      edge &e = G[v][i];
      if (e.cap > 0 && level[e.to] < 0) {
        level[e.to] = level[v] + 1;
        que.push(e.to);
      }
    }
  }
}
int dfs(int v, int t, int f) {
  if (v == t) return f;
  for (int &i = iter[v]; i < (int)G[v].size(); i++) {
    edge &e = G[v][i];
    if (e.cap > 0 && level[v] < level[e.to]) {
      int d = dfs(e.to, t, min(f, e.cap));
      if (d > 0) {
        e.cap -= d;
        G[e.to][e.rev].cap += d;
        return d;
      }
    }
  }
  return 0;
}
int max_flow(int s, int t, int lim) {
  int flow = 0;
  for (;;) {
    bfs(s);
    if (level[t] < 0 || lim == 0) return flow;
    memset(iter, 0, sizeof(iter));
    int f;
    while ((f = dfs(s, t, lim)) > 0) {
      flow += f;
      lim -= f;
    }
  }
}
int max_flow(int s, int t) { return max_flow(s, t, 1 << 28); }
bool back_edge(int s, int t, int from, int to) {
  for (int i = 0; i < (int)G[from].size(); i++) {
    edge &e = G[from][i];
    if (e.to == to) {
      if (e.cap == 0 && max_flow(from, to, 1) == 0) {
        max_flow(from, s, 1);
        max_flow(t, to, 1);
        return 1;
      }
    }
  }
  return 0;
}
signed main() {
  int n, m;
  cin >> n >> m;
  int S = n + m * 3, T = n + m * 3 + 1;
  for (int i = 0; i < n; i++) add_edge(S, i, 1);
  for (int i = 0; i < m; i++) add_edge(n + i, T, 1);
  for (int i = 1; i < m; i++) add_edge(n + m + i, n + m + i - 1, 1 << 28);
  for (int i = 0; i < m - 1; i++)
    add_edge(n + m * 2 + i, n + m * 2 + i + 1, 1 << 28);
  for (int i = 0; i < m; i++) {
    add_edge(n + m + i, n + i, 1 << 28);
    add_edge(n + m * 2 + i, n + i, 1 << 28);
  }
  for (int i = 0; i < n; i++) {
    int l, r;
    cin >> l >> r;
    l--;
    r--;
    add_edge(i, n + m + l, 1);
    add_edge(i, n + m * 2 + r, 1);
  }
  cout << n - max_flow(S, T) << endl;
  return 0;
}
