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#include <iostream>
#include <vector>
#include <algorithm>

std::vector<std::pair<int, int> > merge(const std::vector<std::pair<int, int> > &vec) {
    std::vector<std::pair<int, int> > res;
    std::pair<int, int> actualInterval;
    if (!vec.empty()) {
        actualInterval = *vec.begin();
    }
    for (auto interval : vec) {
        if (interval.first <= actualInterval.second) {
            if (interval.second > actualInterval.second) {
                actualInterval.second = interval.second;
            }
        } else {
            res.push_back(actualInterval);
            actualInterval = interval;
        }
    }
    if (!vec.empty()) {
        res.push_back(actualInterval);
    }
    return res;
}

std::pair<int, int> getIntersection(std::pair<int, int> p1, std::pair<int, int> p2) {
    int l, r;
    if (p1.first < p2.first) {
        l = p2.first;
    } else {
        l = p1.first;
    }
    if (p1.second > p2.second) {
        r = p2.second;
    } else {
        r = p1.second;
    }
    return std::make_pair(l, r);
}

std::vector<std::pair<int, int> >
intersect(const std::vector<std::pair<int, int> > &vec1, const std::vector<std::pair<int, int> > &vec2) {
    std::vector<std::pair<int, int> > res;
    std::pair<int, int> actualIntersection;
    int i, j;
    i = 0;
    j = 0;

    while (i < vec1.size() && j < vec2.size()) {
        actualIntersection = getIntersection(vec1[i], vec2[j]);
        if (actualIntersection.first <= actualIntersection.second) {
            res.push_back(actualIntersection);
        }
        if (vec1[i].second < vec2[j].second) {
            i++;
        } else {
            j++;
        }
    }
    return res;
}

int main() {
    int n, m;
    std::vector<std::pair<int, int> > yellow, blue, red;
    std::cin >> n >> m;

    for (int i = 0; i < m; i++) {
        int l, r, c;
        std::cin >> l >> r >> c;
        if (c == 1) {
            yellow.emplace_back(l, r);
        }
        if (c == 2) {
            blue.emplace_back(l, r);
        }
        if (c == 3) {
            red.emplace_back(l, r);
        }
    }

    std::sort(yellow.begin(), yellow.end());
    std::sort(blue.begin(), blue.end());
    std::sort(red.begin(), red.end());

    yellow = merge(yellow);
    blue = merge(blue);
    red = merge(red);

    auto green = intersect(yellow, blue);
    auto other = intersect(green, red);
    int res = 0;

    for (auto interval : green) {
        res += interval.second - interval.first + 1;
    }
    for (auto interval : other) {
        res -= interval.second - interval.first + 1;
    }

    std::cout << res << "\n";

    return 0;
}