注意细节

#include <bits/stdc++.h>
using namespace std;
struct node{
	int start,end;
	friend bool operator<(node x,node y){
		return x.end<y.end;
	}
};
int main(void){
	int n;
	vector<node>v;
    while(cin>>n and n!=0){
        v.clear();
    	int start,end;
    	for(int i=0;i<n;++i){
            cin>>start>>end;
    		v.push_back({start,end});
    	}
    	sort(v.begin(),v.end());
        int cnt=1;
    	for(int i=1,last=v[0].end;i<v.size();++i){
    		if(last<=v[i].start) ++cnt,last=v[i].end;
    	}
    	cout<<cnt<<'\n';
    }
    return 0;
}