#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;

const int N = 100010;
vector<pair<int, int>> nums, res;
int n;

int main() {
    scanf("%d", &n);
    int l, r;
    for (int i = 0; i < n; i ++ ) {
        scanf("%d%d", &l, &r);
        nums.push_back({l, r});
    }

    //按左端点排序
    sort(nums.begin(), nums.end());

    int start = -2e9, end = -2e9;
    for(auto item : nums) {
        //情况1：无法合并
        if (end < item.first) {
            if (end != -2e9) res.push_back({l, r});
            start = item.first;
            end = item.second;
        }

        //情况2：可以合并
        if (end >= item.first) {
            if (end <= item.second) end = item.second;
        }
    }

    res.push_back({start, end});
    cout << res.size();
}