#include <iostream>
#include <algorithm>
using namespace std;
typedef struct {
    int le, ri;
    bool iscovered = false;
} mypoint;
bool together(mypoint a, mypoint b) {
    if (a.ri >= b.le && a.ri <= b.ri)
        return true;
    return false;
}
bool cmp(mypoint a, mypoint b) { return a.ri < b.ri; }
mypoint po[1000000];
int main() {
    int n, sum = 0;
    cin >> n;
    for (int i = 0; i < n; i++) cin >> po[i].le >> po[i].ri;
    sort(po, po + n, cmp);
    for (int i = 0; i < n; i++) {
        if (po[i].iscovered)
            continue;
        int j;
        po[i].iscovered = true;
        for (j = i + 1; j < n; j++)
            if (together(po[i], po[j])) {
                po[j].iscovered = true;
            }
        sum++;
    }
    cout << sum;
}