#include<bits/stdc++.h>
using namespace std; 
int n,p;
long long ans;
struct node{
	stack <int> s;
}b[7];
int main(){
	freopen("gitara.in","r",stdin);
	freopen("gitara.out","w",stdout);
	cin>>n>>p;
	int x,y;
	for(int i=1;i<=n;i++){
		cin>>x>>y;
		if(b[x].s.size()&&b[x].s.top()<y){
			b[x].s.push(y);
			ans++;
		}
		else if(b[x].s.size()&&b[x].s.top()>y){
			while(b[x].s.size()&&b[x].s.top()>y){
				b[x].s.pop();
				ans++;
			}
			if(b[x].s.size()&&b[x].s.top()!=y){
				b[x].s.push(y);
				ans++;
			}
		}
		if(!b[x].s.size()){
			b[x].s.push(y);
			ans++;
		}
	} 
	cout<<ans;
	return 0;
}