#include <iostream>
#include <stdio.h>
#include <string.h>
#include <algorithm>
#define MAX_N 1000005
#define N 1000000

using namespace std;

struct Data {
    int l, r;
    Data() {}
    Data(int _l, int _r) : l(_l), r(_r) {}
    friend bool operator<(const Data &a, const Data &b) { return a.l != b.l ? a.l < b.l : a.r < b.r; }
};

int n, ans = 0;
int w[MAX_N];
Data a[MAX_N];

void update(int k, int x) {
    for (int i = k; i <= N; i += i & -i) {
        w[i] = max(w[i], x);
    }
}

int query(int k) {
    int ans = 0;
    for (int i = k; i > 0; i -= i & -i) {
        ans = max(ans, w[i]);
    }
    return ans;
}

int main() {
    scanf("%d", &n);
    for (int i = 1; i <= n; i++) {
        scanf("%d%d", &a[i].l, &a[i].r);
    }
    sort(a + 1, a + 1 + n);
    for (int i = 1; i <= n; i++) {
        int t = query(a[i].l - 1) + 1;
        ans = max(ans, t);
        update(a[i].r, t);
    }
    printf("%d\n", ans);
}