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

typedef unsigned long long ull;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> PII;
typedef pair<ll, int> PILL;
typedef pair<ll, ll> PLL;

const int MAX_N = 1e6+5;
const int M = 1e6;
const ll INF = (ll)(1e18);
const int inf = 2e9;
const ll MOD = 1000000007LL;

int n, m;
int yellow[MAX_N], blue[MAX_N], red[MAX_N];

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
	
	cin >> n >> m;
	for (int i = 0; i < m; i++) {
		int l, r, k;
		cin >> l >> r >> k;
		if (k == 1) {
			yellow[l]++;
			yellow[r+1]--;
		} else if (k == 2) {
			blue[l]++;
			blue[r+1]--;
		} else {
			red[l]++;
			red[r+1]--;
		}
	}
	
	for (int i = 1; i <= n; i++) {
		yellow[i] += yellow[i-1];
		blue[i] += blue[i-1];
		red[i] += red[i-1];
	}
	
	int ans = 0;
	for (int i = 1; i <= n; i++) {
		if (yellow[i] > 0 && blue[i] > 0 && red[i] == 0) ans++;
	}
	
	cout << ans << '\n';
	
    return 0;
}