#include<bits/stdc++.h>
using namespace std;
struct act{
int begin;
int end;
}a[1010];
int cmp(act x,act y){
return x.end < y.end;
}
int main(){
int n;
cin>>n;
for(int i = 0 ; i < n ; i++){
cin>>a[i].begin>>a[i].end;
}
sort(a,a + n,cmp);
int last = a[0].end;
int sum = 1;
for(int i = 0 ; i < n ; i++){
if(last <= a[i].begin){
sum++;
last = a[i].end;
}
}
cout<<sum;
return 0;
}
