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#pragma GCC optimize("O3")
#define _USE_MATH_DEFINES
#include <bits/stdc++.h>

#define BOOST ios::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define FOR(a, b, c) for(int a = b; a < c; ++a)
#define PB push_back
#define MP make_pair
#define INF (int)1e9+7
#define LLINF 2e18+7
#define ALL(a) a.begin(), a.end()
#define SIZE(a) (int)a.size()

typedef unsigned long long ULL;
typedef long long LL;
typedef long double LD;

using namespace std;

//#define DEBUG

const int MAX = 1e6 + 7;

int barwniki[MAX][3];

int main()
{
    #ifndef DEBUG
    BOOST;
    #endif

    int n, m;
    cin >> n >> m;

    FOR(i, 0, m)
    {
        int l, r, k;
        cin >> l >> r >> k;
        --k;

        barwniki[l][k]++;
        barwniki[r + 1][k]--;
    }

    int res = 0;

    FOR(i, 1, n + 1)
    {
        FOR(j, 0, 3)
        {
            barwniki[i][j] += barwniki[i - 1][j];
        }

        if(barwniki[i][0] > 0 && barwniki[i][1] > 0 && barwniki[i][2] == 0)
            ++res;
    }

    cout << res << "\n";
    
    return 0;
}