#include <bits/stdc++.h>
using namespace std;

const int INF=-1e9-5;
const int N=1e5+5;

struct Range{
    int l, r;
    bool operator< (const Range &o) const{
        return r<o.r;
    }
}range[N];
int n;

int main(){
    // 贪心策略
    cin>>n;
    int a, b;
    for(int i=0; i<n; ++i){
        cin>>a>>b;
        range[i]={a, b};
    }
    sort(range, range+n);
    int END=range[0].r;
    int cnt=1;
    for(int i=1; i<n; ++i){
        if(range[i].l>END){
            END=range[i].r;
            ++cnt;
        }
    }
    cout<<cnt<<endl;
    return 0;
}