#include <bits/stdc++.h>
template <typename T>
inline T max(T a, T b) {
  return a > b ? a : b;
}
template <typename T>
inline T min(T a, T b) {
  return a < b ? a : b;
}
template <typename T>
inline T abs(T a) {
  return a > 0 ? a : -a;
}
template <typename T>
inline bool repr(T &a, T b) {
  return a < b ? a = b, 1 : 0;
}
template <typename T>
inline bool repl(T &a, T b) {
  return a > b ? a = b, 1 : 0;
}
template <typename T>
inline T gcd(T a, T b) {
  T t;
  if (a < b) {
    while (a) {
      t = a;
      a = b % a;
      b = t;
    }
    return b;
  } else {
    while (b) {
      t = b;
      b = a % b;
      a = t;
    }
    return a;
  }
}
template <typename T>
inline T sqr(T x) {
  return x * x;
}
struct Cg {
  inline char operator()() { return getchar(); }
};
struct Cp {
  inline void operator()(char x) { putchar(x); }
};
inline bool IS(char x) { return x == 10 || x == 13 || x == ' '; }
template <typename T>
struct Fr {
  T P;
  inline Fr &operator,(int &x) {
    x = 0;
    char t = P();
    while ((t < '0' || t > '9') && t != '-') t = P();
    bool f = 0;
    if (t == '-') t = P(), f = 1;
    x = t - '0';
    for (t = P(); t >= '0' && t <= '9'; t = P()) x = x * 10 + t - '0';
    if (f) x = -x;
    return *this;
  }
  inline operator int() {
    int x;
    *this, x;
    return x;
  }
  inline Fr &operator,(long long &x) {
    x = 0;
    char t = P();
    while ((t < '0' || t > '9') && t != '-') t = P();
    bool f = 0;
    if (t == '-') t = P(), f = 1;
    x = t - '0';
    for (t = P(); t >= '0' && t <= '9'; t = P()) x = x * 10 + t - '0';
    if (f) x = -x;
    return *this;
  }
  inline operator long long() {
    long long x;
    *this, x;
    return x;
  }
  inline Fr &operator,(char &x) {
    for (x = P(); IS(x); x = P())
      ;
    return *this;
  }
  inline operator char() {
    char x;
    *this, x;
    return x;
  }
  inline Fr &operator,(char *x) {
    char t = P();
    for (; IS(t); t = P())
      ;
    if (~t) {
      for (; !IS(t) && ~t; t = P()) *x++ = t;
    }
    *x++ = 0;
    return *this;
  }
  inline Fr &operator,(double &x) {
    x = 0;
    char t = P();
    while ((t < '0' || t > '9') && t != '-') t = P();
    bool f = 0;
    if (t == '-') t = P(), f = 1;
    x = t - '0';
    for (t = P(); t >= '0' && t <= '9'; t = P()) x = x * 10 + t - '0';
    if (t == '.') {
      double u = 0.1;
      for (t = P(); t >= '0' && t <= '9'; t = P(), u *= 0.1) x += u * (t - '0');
    }
    if (f) x = -x;
    return *this;
  }
  inline operator double() {
    double x;
    *this, x;
    return x;
  }
  inline Fr &operator,(long double &x) {
    x = 0;
    char t = P();
    while ((t < '0' || t > '9') && t != '-') t = P();
    bool f = 0;
    if (t == '-') t = P(), f = 1;
    x = t - '0';
    for (t = P(); t >= '0' && t <= '9'; t = P()) x = x * 10 + t - '0';
    if (t == '.') {
      double u = 0.1;
      for (t = P(); t >= '0' && t <= '9'; t = P(), u *= 0.1) x += u * (t - '0');
    }
    if (f) x = -x;
    return *this;
  }
  inline operator long double() {
    long double x;
    *this, x;
    return x;
  }
  inline Fr &operator,(unsigned int &x) {
    x = 0;
    char t = P();
    while (t < '0' || t > '9') t = P();
    x = t - '0';
    for (t = P(); t >= '0' && t <= '9'; t = P()) x = x * 10 + t - '0';
    return *this;
  }
  inline operator unsigned int() {
    unsigned int x;
    *this, x;
    return x;
  }
  inline Fr &operator,(unsigned long long &x) {
    x = 0;
    char t = P();
    while (t < '0' || t > '9') t = P();
    x = t - '0';
    for (t = P(); t >= '0' && t <= '9'; t = P()) x = x * 10 + t - '0';
    return *this;
  }
  inline operator unsigned long long() {
    unsigned long long x;
    *this, x;
    return x;
  }
};
Fr<Cg> in;
template <typename T>
struct Fw {
  T P;
  inline Fw &operator,(int x) {
    if (x) {
      if (x < 0) P('-'), x = -x;
      char s[10], c = 0;
      while (x) s[c++] = x % 10 + '0', x /= 10;
      while (c--) P(s[c]);
    } else
      P('0');
    return *this;
  }
  inline Fw &operator()(int x) {
    if (x) {
      if (x < 0) P('-'), x = -x;
      char s[10], c = 0;
      while (x) s[c++] = x % 10 + '0', x /= 10;
      while (c--) P(s[c]);
    } else
      P('0');
    return *this;
  }
  inline Fw &operator,(unsigned int x) {
    if (x) {
      char s[10], c = 0;
      while (x) s[c++] = x % 10 + '0', x /= 10;
      while (c--) P(s[c]);
    } else
      P('0');
    return *this;
  }
  inline Fw &operator()(unsigned int x) {
    if (x) {
      char s[10], c = 0;
      while (x) s[c++] = x % 10 + '0', x /= 10;
      while (c--) P(s[c]);
    } else
      P('0');
    return *this;
  }
  inline Fw &operator,(long long x) {
    if (x) {
      if (x < 0) P('-'), x = -x;
      char s[19], c = 0;
      while (x) s[c++] = x % 10 + '0', x /= 10;
      while (c--) P(s[c]);
    } else
      P('0');
    return *this;
  }
  inline Fw &operator()(long long x) {
    if (x) {
      if (x < 0) P('-'), x = -x;
      char s[19], c = 0;
      while (x) s[c++] = x % 10 + '0', x /= 10;
      while (c--) P(s[c]);
    } else
      P('0');
    return *this;
  }
  inline Fw &operator,(unsigned long long x) {
    if (x) {
      char s[20], c = 0;
      while (x) s[c++] = x % 10 + '0', x /= 10;
      while (c--) P(s[c]);
    } else
      P('0');
    return *this;
  }
  inline Fw &operator()(unsigned long long x) {
    if (x) {
      char s[20], c = 0;
      while (x) s[c++] = x % 10 + '0', x /= 10;
      while (c--) P(s[c]);
    } else
      P('0');
    return *this;
  }
  inline Fw &operator,(char x) {
    P(x);
    return *this;
  }
  inline Fw &operator()(char x) {
    P(x);
    return *this;
  }
  inline Fw &operator,(const char *x) {
    while (*x) P(*x++);
    return *this;
  }
  inline Fw &operator()(const char *x) {
    while (*x) P(*x++);
    return *this;
  }
  inline Fw &operator()(double x, int y) {
    if (y) {
      double t = 0.5;
      for (int i = y; i--;) t *= 0.1;
      if (x >= 0)
        x += t;
      else
        x -= t, P('-');
      *this, (long long)(abs(x));
      P('.');
      if (x < 0) x = -x;
      while (y--) {
        x *= 10;
        x -= floor(x * 0.1) * 10;
        P(((int)x) % 10 + '0');
      }
    } else if (x >= 0)
      *this, (long long)(x + 0.5);
    else
      *this, (long long)(x - 0.5);
    ;
    return *this;
  }
  inline Fw &operator()(long double x, int y) {
    if (y) {
      double t = 0.5;
      for (int i = y; i--;) t *= 0.1;
      if (x >= 0)
        x += t;
      else
        x -= t, P('-');
      *this, (long long)(abs(x));
      P('.');
      if (x < 0) x = -x;
      while (y--) {
        x *= 10;
        x -= floor(x * 0.1) * 10;
        P(((int)x) % 10 + '0');
      }
    } else if (x >= 0)
      *this, (long long)(x + 0.5);
    else
      *this, (long long)(x - 0.5);
    ;
    return *this;
  }
};
Fw<Cp> out;
const int N = 800111, M = 1633221;
struct edge {
  int to, w, ne;
} e[M * 2 + 2];
int p[N + 1], p2[N + 1], em = 2, dep[N + 1], q[N + 1], qe, fl[N + 1], tm[N + 1],
                         T;
inline void add(int a, int b, int w) {
  e[em].to = b, e[em].w = w, e[em].ne = p[a], p[a] = em++;
  e[em].to = a, e[em].w = 0, e[em].ne = p[b], p[b] = em++;
}
bool dfs(int s, int t) {
  if (s == t) return 1;
  for (int &j = p2[s]; j; j = e[j].ne)
    if (tm[e[j].to] != T && e[j].w && dep[e[j].to] == dep[s] + 1) {
      tm[e[j].to] = T;
      fl[e[j].to] = min(e[j].w, fl[s]);
      if (dfs(e[j].to, t)) {
        e[j].w -= fl[t];
        e[j ^ 1].w += fl[t];
        return 1;
      }
    }
  dep[s] = -1;
  return 0;
}
inline int dinic(int s, int t) {
  int flow = 0;
  while (1) {
    memset(dep, 0, sizeof(dep));
    q[0] = s, qe = 1, dep[s] = 1;
    ++T;
    for (int i = 0; i ^ qe; i++) {
      tm[q[i]] = T;
      for (int j = p[q[i]]; j; j = e[j].ne)
        if (!dep[e[j].to] && e[j].w) {
          dep[e[j].to] = dep[q[i]] + 1;
          q[qe++] = e[j].to;
        }
    }
    if (tm[t] != T) break;
    for (int i = 0; i ^ qe; i++) p2[q[i]] = p[q[i]];
    while (1) {
      fl[s] = 0x7fffffff;
      ++T;
      dfs(s, t);
      if (tm[t] != T) break;
      flow += fl[t];
    }
  }
  return flow;
}
int n, m, ls[N], rs[N];
int main() {
  in, n, m;
  int t = m, S = ++t, T = ++t;
  for (int i = 1, iend = m; i <= iend; i++) add(i, T, 1);
  for (int i = 1, iend = m; i <= iend; i++) {
    ls[i] = ++t;
    add(ls[i], ls[i - 1], 1e9);
    add(ls[i], i, 1);
  }
  for (int i = m; i; i--) {
    rs[i] = ++t;
    add(rs[i], rs[i + 1], 1e9);
    add(rs[i], i, 1);
  }
  for (int i = 1, iend = n; i <= iend; i++) {
    int l, r, v = ++t;
    in, l, r;
    add(v, ls[l], 1);
    add(v, rs[r], 1);
    add(S, v, 1);
  }
  int flow = dinic(S, T);
  out, n - flow, '\n';
}
