#include<bits/stdc++.h> 
#define int long long
using namespace std;
ifstream fin("gitara.in");
ofstream fout("gitara.out");
auto mread = [](){
    int x;
    fin >> x;
    return x;
};
const int N = 5e5 + 5;
int n = mread(), p = mread(), a[N], b[N];
vector<int> v[7];
priority_queue<int> q[7];
signed main(){
    for(int i = 1; i <= n; i ++){
        a[i] = mread(), b[i] = mread();
        v[a[i]].push_back(b[i]);
    }
    int ans = 0;
    for(int i = 1; i <= 6; i ++){
        for(int x : v[i]){
            while(q[i].size() && q[i].top() > x){
                ans ++;
                q[i].pop();
            }
            if(q[i].empty() || q[i].top() < x){
                ans ++;
                q[i].push(x);
            }
        }
    }
    fout << ans;
    return 0;
}