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#include<bits/stdc++.h>
#define f first
#define s second
#define mp make_pair
#define pb push_back
#define pii pair<int, int>
#define pll pair<long long, long long>
#define ll long long
#define vi vector<int>
#define vl vector<ll>
#define rep(i,p,k) for(ll i=p; i<k; i++)
#define per(i,p,k) for (ll i=k-1;i>=p;i--)

ll gcd(ll a,ll b) {return b?gcd(b,a%b):a;}

using namespace std;

vector<pii>tab[1000005];
int kolory[4];

int main() {
    ios_base::sync_with_stdio(0);
    int n, m;
    cin >> n >> m;

    rep(i, 0, m) {
        int l, r, k;
        cin >> l >> r >> k;
        tab[l].pb(mp(k, 1));
        tab[r+1].pb(mp(k, -1));
    }

    int wyn = 0;

    rep(i, 1, n+1) {
        rep(j, 0, tab[i].size()) {
            kolory[tab[i][j].f] += tab[i][j].s;
        }
        if(kolory[1] > 0 && kolory[2] > 0 && kolory[3] == 0)
            wyn++;
    }
    cout<<wyn<<endl;
}