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

const int MAX_N = 1000005;

int a[MAX_N][4];

int main(){
	ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
	int n, m;
	cin >> n >> m;
	for (int i = 1; i <= m; ++i){
		int l, r, k;
		cin >> l >> r >> k;
		a[l][k]++;
		a[r+1][k]--;
	}
	int res = 0;
	for (int i = 1; i <= n; ++i){
		a[i][1] += a[i-1][1];
		a[i][2] += a[i-1][2];
		a[i][3] += a[i-1][3];

		if (a[i][1] && a[i][2] && !a[i][3])
			res++;
	}

	cout << res << "\n";
}