#include <stdio.h>
#include <string.h>
#include <string>
#include <vector>
#include <sstream>
#include <algorithm>
#include <iostream>
#include <cmath>
using namespace std;

#define FOR(i,n) for (int i = 0; i < n; i++)
#define abs(x) ((x)<0?(-(x)):(x))
#define REP(i,v) for (unsigned i = 0; i < v.size(); i++)
#define RL(i,v) for (unsigned i = 0; i < v.length(); i++)
typedef long long ll;


void solve(void)
{
	FILE* f = fopen("bdz.in", "rt");
	FILE* fo = fopen("bdz.out", "wt");

	int n, m;
	static int a[131072];
	memset(a, 0, sizeof(a));
	
	fscanf(f, "%d %d", &n, &m);
	for (int i = 0; i < m; i++)
	{
		int cnt, x, y;
		fscanf(f, "%d %d %d", &cnt, &x, &y);
		for (int c = x; c < y; c++)
			a[c] += cnt;
	}
	int ans = 0;
	for (int i = 0; i < 131072; i++)
		ans = max(ans, a[i] / 64 + !!(a[i] % 64));
	fprintf(fo, "%d\n", ans);
	
	fclose(f);
	fclose(fo);
}


int main(void)
{
	solve();
	return 0;
}