#include <bits/stdc++.h>
using namespace std;
#define f(i,k,n) for(int i=k; i<n; i++)
#define ll long long
const int inf = INT_MAX;

void solve()
{
    int n,m;
    cin>>n>>m;
    int x,y;
    vector<vector<int>> a;
    f(i,0,m)
    {
        cin>>x>>y;
        a.push_back({x,y});
    }
    sort(a.begin(),a.end());
    int c=0;
    int e=1;
    f(i,0,m)
    {
        if(e<a[i][0])   c++;
        e=max(e,a[i][1]);
    }
    if(e<n) c++;
    cout<<c;
}

int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    int t=1;
    //cin>>t;
    while(t--)  solve();
    return 0;
}