#include <bits/stdc++.h>
            
using namespace std;

int n, p, ans = 0;
struct node
{
    priority_queue<int,vector<int>,less<int> > q;
};
node v[10];
    
int main()
{
    freopen("gitara.in", "r", stdin);
    freopen("gitara.out", "w", stdout);
        
    ios::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
            
    cin >> n >> p;
    for(int i = 1; i <= n; ++i)
    {
        int x, y;
        cin >> x >> y;
        if(v[x].q.size() == 0)
        {
            v[x].q.push(y);
            ans++;
        }
        else if(v[x].q.top() < y)
        {
            v[x].q.push(y);
            ans++;    
        }
        else
        {
            while(v[x].q.size() > 0 && v[x].q.top() > y)
            {
                v[x].q.pop();
                ans++;
            }
            if(v[x].q.size() == 0 || v[x].q.top() < y)
            {
                v[x].q.push(y);
                ans++;
            }
        }
    }
    cout << ans;
    
   	return 0;
}