1 #include<cstdio>
2 #include<algorithm>
3 #include<vector>
4 using namespace std;
5 typedef pair<int,int> PII;
6 const int N=1e5+10;
7 vector<PII> merge(vector<PII> &v)
8 {
9 int st=-2e9,ed=-2e9;
10 vector<PII>c;
11 for(int i=0;i<v.size();i++)
12 if(v[i].first>ed)
13 {
14 if(ed!=-2e9)
15 c.push_back({st,ed});
16 st=v[i].first;
17 ed=v[i].second;
18 }
19 else ed=max(ed,v[i].second);
20 if(st!=-2e9) c.push_back({st,ed});
21 return c;
22 }
23 int main()
24 {
25 vector<PII> v,c;
26 int n;
27 scanf("%d",&n);
28 for(int i=0;i<n;i++)
29 {
30 int l,r;
31 scanf("%d%d",&l,&r);
32 v.push_back({l,r});
33 }
34 sort(v.begin(),v.end());
35 c=merge(v);
36 printf("%d\n",c.size());
37 return 0;
38 }