#include<bits/stdc++.h>
using namespace std;
int b[105],e[105];
int main()
{
    int n;
    cin>>n;
    for(int i = 1;i<=n;i++)
    {
        cin>>b[i]>>e[i];
    }
    for(int i = 1;i<=n-1;i++)
    {
        for(int j = 1;j<=n-i;j++)
        {
            if(e[j] > e[j+1])
            {
                swap(e[j],e[j+1]);
                swap(b[j],b[j+1]);
            }
        }
    }
    // for(int i = 1;i<=n;i++)
    // {
    //     cout<<b[i]<<" "<<e[i]<<endl;
    // }
    int end = e[1];
    int c = 1;
    for(int i = 2;i<=n;i++)
    {
        if(b[i] >= end)
        {
            c++;
            end = e[i];
        }
    }
    cout<<c;
}
/**************************************************************
	Problem: 1372
	User: wuyichen
	Language: C++
	Result: Accepted
	Time:12 ms
	Memory:2072 kb
****************************************************************/