#include<bits/stdc++.h>
using namespace std;
long long n,m,s,p;
struct nm{
    long long x,y;
}a[200005];
bool c(nm x,nm y){
    return x.x<y.x;
}
int main(){
    freopen("bridge.in","r",stdin);
    freopen("bridge.out","w",stdout);
    cin>>n>>m;
    for(int i=1;i<=m;i++){
        cin>>a[i].x>>a[i].y;
    }
    sort(a+1,a+m+1,c);
    p=10000000000000;
    for(int i=m;i>=1;i--){
        if(a[i].y<=p) s++,p=a[i].x;
    }
    cout<<s;
	return 0;
}