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#include <iostream>
#include <list>

using namespace std;

class Color {
    int r;
    int b;
    int y;

public:
    Color(int rr, int bb, int yy) : r(rr), b(bb), y(yy) {}

    Color minus() const {
        return {-r, -b, -y};
    }

    int sum() const {
        return r + b + y;
    }

    bool isGreen() const {
        return r == 0 && b > 0 && y > 0;
    }

    bool isNegative() const {
        return sum() < 0;
    }

    void mix(Color c) {
        r += c.r;
        b += c.b;
        y += c.y;
    }
};

class Point {
    int x;
    Color c;

public:
    Point(int xx, Color cc) : x(xx), c(cc) {}

    int getX() const {
        return x;
    }

    Color getColor() const {
        return c;
    }

    int getColorSum() const {
        return c.sum();
    }

    bool wasEnd() const {
        return c.isNegative();
    }

    bool operator<(const Point &p) const {
        if (getX() == p.getX()) {
            return getColorSum() > p.getColorSum();
        }

        return getX() < p.getX();
    }
};

Color getColor(int k) {
    switch (k) {
        case 1:
            return {0, 0, 1};
        case 2:
            return {0, 1, 0};
        case 3:
            return {1, 0, 0};
        default:
            return {0, 0, 0};
    }
}

int main() {

    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

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

    list<Point> points;

    for (int i = 0; i < m; i++) {
        int l, r, k;
        cin >> l >> r >> k;

        Color color = getColor(k);
        points.emplace_back(l, color);
        points.emplace_back(r, color.minus());
    }

    points.sort();

    Color currentColor = getColor(0);
    Point lastPoint = Point(0, getColor(0));
    int lastCounted = 0;
    int result = 0;

    for (Point const &point : points) {
        if (point.getX() == lastPoint.getX()) {
            if (point.getColor().isNegative() != lastPoint.getColor().isNegative()) {
                if (currentColor.isGreen()) {
                    result++;
                }
                lastCounted = point.getX();
            }
        } else {
            if (currentColor.isGreen()) {
                if (point.getColor().isNegative()) {
                    result += point.getX() - lastCounted;
                    lastCounted = point.getX();
                } else {
                    result += point.getX() - 1 - lastCounted;
                    lastCounted = point.getX() - 1;
                }
            } else {
                if (point.getColor().isNegative()) {
                    lastCounted = point.getX();
                } else {
                    lastCounted = point.getX() - 1;
                }
            }
        }
        currentColor.mix(point.getColor());
        lastPoint = point;
    }

    if (currentColor.isGreen()) {
        if (n - lastCounted > 0) {
            result += n - lastCounted;
        }
    }

    cout << result << endl;

    return 0;
}