#include <bits/stdc++.h>
using namespace std;
long long n,p,res;
deque<int>a[10];
int main () {
    freopen("gitara.in","r",stdin);
    freopen("gitara.out","w",stdout);
    cin >> n >> p;
    for (int i=1;i<=n;i++) {
        int x,y;
        cin >> x >> y;
        while (a[x].size()&&a[x].back()>y) {
            res++;
            a[x].pop_back();
        }
        if (a[x].size()==0||a[x].back()!=y) {
            a[x].push_back(y);
            res++;
        }
    }
    cout << res <<endl;
    return 0;
}