#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]);
            }
        }
    }
    int end=e[1];
    int c=1;
    for(int i=2;i<=n;i++){
        if(b[i]>=end){
            c++;
            end=e[i];
        }
    }
    cout<<c;
    return 0;
}
/**************************************************************
	Problem: 1372
	User: luyanchen
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/