#include <cstdio>
#include <stack>
using namespace std;
const int N = 9;
int n, p, x, y;
int s, t, u, v;
stack<int> q[N];
int main() {
    freopen("gitara.in", "r", stdin);
    freopen("gitara.out", "w", stdout);
    scanf("%d %d", &n, &p);
    for(int i=0; i<n; i++) {
        scanf("%d %d", &x, &y);
        if(!q[u = x].empty())
            v = q[u].top();
        else v = 0;
        if(v < y) {
            q[u].push(y);
            //fprintf(stderr, "(push %d) ", q[u].top());
            s++;
        } else if(v > y) {
            while(!q[u].empty() && q[u].top() > y) {
                //fprintf(stderr, "(pop %d) ", q[u].top());
                q[u].pop();
                s++;
            }
            if(q[u].empty() || q[u].top() < y) {
                q[u].push(y);
                //fprintf(stderr, "(push %d) ", q[u].top());
                s++;
            }
        }
        //fprintf(stderr, "%d %d %d %d, %d\n", u, v, x, y, s);
    }
    printf("%d\n", s);
    return 0;
}