#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
struct segment {
    int a;
    int b;
};

bool compare(const segment &x, const segment &y);
struct segment seg[1000100];

int main() {
    int k;
    int res = 0;
    cin >> k;
    for (int i = 0; i < k; i++) {
        cin >> seg[i].a >> seg[i].b;
    }
    sort(seg, seg + k, compare);
    int rmax = -1;
    for (int i = 0; i < k; i++) {
        if (seg[i].a > rmax) {
            rmax = seg[i].b;
            ++res;
        }
    }
    cout << res;
    /*
    for(int i = 0; i < k; i++) {
            cout << seg[i].a << " " << seg[i].b << endl;
    }
    */
    return 0;
}

bool compare(const segment &x, const segment &y) {
    if (x.b != y.b) {
        return x.b < y.b;
    } else
        return x.a < y.a;
}