#include<iostream>
#include<vector>
#include<algorithm>

using namespace std;

typedef pair<int, int> pii;

vector<pii> nums, res;

int main(){
	int st = -2e9, ed = -2e9;
	int n;
	scanf("%d", &n);
	while(n --){
		int l, r;
		scanf("%d%d", &l, &r);
		nums.push_back({l, r});
	}
	sort(nums.begin(), nums.end());
	for(auto num : nums){
		if(ed < num.first){
			if(ed != -2e9) res.push_back({st, ed});
			st = num.first;
			ed = num.second;
		}
		else if(ed < num.second) ed = num.second;
	}
	
	if(st != -2e9 && ed != -2e9) res.push_back({st, ed});
	
	printf("%d", res.size());
	return 0;
}