#include<bits/stdc++.h>
using namespace std;
#define ll long long
struct node{
    priority_queue <ll> q;
}s[10];
ll n,p,x,y,ans;
int main(){
    freopen("gitara.in","r",stdin);
    freopen("gitara.out","w",stdout);
    cin>>n>>p;
    for(int i=1;i<=n;i++){
        cin>>x>>y;
        while(!s[x].q.empty()){
            if(s[x].q.top()>y){
                ans++;
                s[x].q.pop();
            }else break;
        }
        if(!s[x].q.empty()){
            if(s[x].q.top()==y)continue;
        }
        s[x].q.push(y);
        ans++;
    }
    cout<<ans;
    return 0;
}