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/*
 * https://sio2.mimuw.edu.pl/c/pa-2020-1/p/kol/
 */

#include <iostream>
#include <vector>
#include <cassert>
#include <bitset>

using namespace std;

struct color {
    int y = 0;
    int b = 0;
    int r = 0;
};

int main() {
    int n, m;

    std::cin >> n >> m;

    vector<color> colors(n);

    for (int i = 0 ; i < m; ++i) {
        int l, r, k;
        std::cin >> l >> r >> k;
        if (k == 1) {
            colors[l-1].y += 1;
            colors[r].y -= 1;
        } else if (k == 2) {
            colors[l-1].b += 1;
            colors[r].b -= 1;
        }  else if (k == 3) {
            colors[l-1].r += 1;
            colors[r].r -= 1;
        } else {
            assert(false);
        }
    }

    int ctr = 0;

    color current_color;

    for (int i = 0 ; i < n; ++i) {
        color c = colors[i];

        current_color.y += c.y;
        current_color.b += c.b;
        current_color.r += c.r;

        if (current_color.y > 0 && current_color.b > 0 && current_color.r == 0) {
            ctr++;
        }
    }

    std::cout << ctr << std::endl;

}