#include <bits/stdc++.h>
using namespace std;
struct node
{
int a;
int b;
}w[1145];
int n;
bool cmp(node x,node y)
{
return x.b < y.b;
}
int main() {
cin>>n;
for(int i = 1;i <= n;i++)
{
cin>>w[i].a>>w[i].b;
}
sort(w + 1,w + 1 + n,cmp);
int sum = 1;
int last = w[1].b;
for(int i = 2;i <= n;i++)
{
if(w[i].a >= last)
{
sum++;
last = w[i].b;
}
}
cout<<sum<<endl;
return 0;
}