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//#pragma GCC optimize("Ofast")
//#pragma GCC optimize ("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

#pragma warning(disable:4786)
#pragma warning(disable:4996)
#include <random>
#include <chrono>
#include <ctime>
#include<list>
#include <numeric>
#include<bitset>
#include<iostream>
#include<cstdio>
#include<algorithm>
#include<vector>
#include<set>
#include<map>
#include<functional>
#include<string>
#include<cstring>
#include<cstdlib>
#include<queue>
#include<utility>
#include<fstream>
#include<sstream>
#include<cmath>
#include<stack>
#include<assert.h>
#include<unordered_map>
#include<unordered_set>
#include <array>
#include <complex>
using namespace std;

#define MEM(a, b) memset(a, (b), sizeof(a))
#define CLR(a) memset(a, 0, sizeof(a))
#define MAX(a, b) ((a) > (b) ? (a) : (b))
#define MIN(a, b) ((a) < (b) ? (a) : (b))
#define ABS(X) ( (X) > 0 ? (X) : ( -(X) ) )
#define S(X) ( (X) * (X) )
#define SZ(V) (int )V.size()
#define FORN(i, n) for(int i = 0; i < n; i++)
#define FORAB(i, a, b) for(int i = a; i <= b; i++)
#define ALL(V) V.begin(), V.end()
#define IN(A, B, C)  ((B) <= (A) && (A) <= (C))
#define AIN(A, B, C) assert(IN(A, B, C))

typedef long long int LL;
//typedef __int128 LLL;
typedef long long LLL;

typedef pair<int, int> PII;
typedef pair<LL, LL> PLL;
typedef pair<double, double> PDD;
typedef vector<int> VI;
typedef vector<LL> VL;
typedef vector<PLL> VPL;
typedef vector<PII> VP;
typedef vector<double> VD;
typedef vector<vector<int>> VVI;
typedef vector<string> VS;
typedef long double ld;

#define MAXN 203
#define MAXN2 MAXN*MAXN
//#define MAXN 1006

const LL MOD = 1000000007;
//const LL MOD = 998244353;
//const LL INF = 2000000000000000001LL; //2e18 + 1


void solve(int ks) {
	int n, m;
	scanf("%d %d", &n, &m);
	VP V;
	while (m--) {
		int l, r, k;
		scanf("%d %d %d", &l, &r, &k);
		V.push_back({ l, k });
		V.push_back({ r + 1, -k });
	}
	sort(ALL(V));
	int cnt[4] = { 0, 0, 0, 0 };
	int j = 0;
	int ans = 0;
	for (int i = 1; i <= n; i++) {
		while (j < SZ(V) && i == V[j].first) {
			if (V[j].second > 0) cnt[V[j].second]++;
			else cnt[-V[j].second]--;
			j++;
		}
		if (cnt[1] && cnt[2] && !cnt[3]) ans++;
	}
	printf("%d\n", ans);
}

void gen() {
}

int main()
{
	double start_time = clock();
#ifdef LOCAL
	freopen("C:\\Home\\Contests\\F\\sample.in", "r", stdin);
	//	freopen("out.out", "w", stdout);
#endif

	gen();

	if (0) {
		int T;
		scanf("%d", &T);
		//AIN(T, 1, 5000);
		for (int ks = 1; ks <= T; ks++) {
			solve(ks);
			//if (ks % 1 == 0) fprintf(stderr, "%d done\n", ks);
		}
	}
	else {
		solve(0);
	}

	double end_time = clock();
	fprintf(stderr, "Time = %lf\n", (end_time - start_time) / CLOCKS_PER_SEC);

	return 0;
}