#include <bits/stdc++.h>
using namespace std;
struct node {
    int a ,b;
}s[100010];
int n;

bool cmp(node a, node b) {
    return a.b < b.b;
}
int main() {
    int maxn = -0x3f3f3f3f;
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> s[i].a >> s[i].b;
        maxn = max(maxn, s[i].a);
    }
    sort(s + 1, s + n + 1, cmp);
    int ans = 0;
    for (int i = n; i >= 1; i--) {
        if (s[i].a >= maxn) ans++, maxn = s[i].a;
    }
    cout << ans << endl;
    return 0;
}

这里