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

//Macro Shorthands
#define F first
#define S second
#define f(i, n) for (ll i = 0; i <= n; i++)
#define rf(i, n) for (ll i = n; i >= 0; i--)
#define Cf(i, a, b) for (ll i = a; i <= b; i++)
#define Crf(i, b, a) for (ll i = b; i >= a; i--)
#define pb push_back
#define mp make_pair
#define z ((ll)1e9 + 7)
#define every(it, x) for (auto &it : x)
#define SET(it, x)     \
    for (auto &it : x) \
    {                  \
        cin >> it;     \
    }
#define ins insert
#define INF ((ll)1e18)
#define Test  \
    ll T;     \
    cin >> T; \
    while (T--)
#define all(v) v.begin(), v.end()
#define nline cout << endl
#define SZ(v) (ll) v.size()
#define pll pair<ll, ll>

typedef long long ll;
typedef vector<ll> vll;
typedef vector<vector<ll>> vvll;
typedef vector<string> vstr;
typedef vector<char> vchar;
typedef vector<pair<ll, ll>> vpll;
typedef set<ll> sll;
typedef set<string> sstr;
typedef set<pair<ll, ll>> spll;
typedef map<ll, ll> mllll;
typedef map<string, ll> mstrll;
typedef queue<ll> qll;
ll powMod(ll x, ll y)
{
    ll p = 1;
    while (y)
    {
        if (y % 2)
        {
            p = (p * x) % z;
        }
        y /= 2;
        x = (x * x) % z;
    }
    return p;
}
ll CpowMod(ll x, ll y, ll w)
{
    ll p = 1;
    while (y)
    {
        if (y % 2)
        {
            p = (p * x) % w;
        }
        y /= 2;
        x = (x * x) % w;
    }
    return p;
}
ll invMod(ll x) { return powMod(x, z - 2); }
ll CinvMod(ll x, ll w) { return CpowMod(x, w - 2, w); }
ll gcdd(ll a, ll b) { return b == 0 ? a : gcdd(b, a % b); }
const ll mod = 1e9 + 7;
bool cmp(pair<ll,ll>&a,pair<ll,ll>&b)
{
    if(a.first == b.first)
    {
        return a.second < b.second;
    }
    else{
        return a.first < a.second;
    }
    return false;
}
void call()
{
    ll n;cin >> n;
    ll  m ;cin >> m;
    vector<pair<ll,ll>>v(m);
    for(ll i =0 ;i < m;++i)
    {
        ll x,y;cin >> x  >> y;
        v.push_back(make_pair(x,y));
    }
    sort(v.begin(),v.end(),cmp);
    ll ans=0;
    vector<pair<ll,ll>>merged;
    merged.push_back(make_pair(-1,-1));
    for(ll i=0;i<v.size();++i)
    { 
       if(v[i].first < merged.back().second)
       {
           merged.back().second =max(merged.back().second,v[i].second);
       }
       else{
           merged.push_back(v[i]);
       }
    }
    cout << n-merged.size()+1 << endl;
}
int main()
{
    int t = 1;
    //cin >> t;
    while (t--)
    {
        call();
    }
}