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#include <bits/stdc++.h>

using namespace std;

class SegmentTree {
    constexpr static int YELLOW = 1, BLUE = 2, RED = 3;
    constexpr static int white = 0, yellow = 1, blue = 2, green = 3;
    constexpr static int ROOT_ID = 1;

    int size;
    int M;
    vector<vector<int>> cnt;
    vector<set<int>> last_paint;
    vector<bool> red;

    int smallest_bigger_2pow(int);
    void fill_up();

    void paint(int, int);

    tuple<int, int, int, int> r_insert(int, int, int, int, int, int);
    int r_query(int, int, int, int, int);

  public:
    SegmentTree(int size) : size(size), M(smallest_bigger_2pow(size)),
                            cnt(2 * M, vector<int>(4, 0)), last_paint(2 * M), red(2 * M, false) {
        fill_up();
    }

    void insert(int, int, int);
    int query(int, int);

    void print();
};

void SegmentTree::print() {
    cout << "TREE" << endl;
    for (int i = 1; i < cnt.size(); ++i) {
        cout << "Vertex " << i << " ";
        cout << "White: " << cnt[i][white] << " ";
        cout << "Yellow: " << cnt[i][yellow] << " ";
        cout << "Blue: " << cnt[i][blue] << " ";
        cout << "Green: " << cnt[i][green] << endl;
    }
}

int SegmentTree::smallest_bigger_2pow(int n) {
    int ans = 1;
    while (ans < n)
        ans *= 2;
    return ans;
}

void SegmentTree::fill_up() {
    // leaves
    for (int i = 0; i < size; ++i) {
        cnt[M + i][white] = 1;
    }

    int l = M, r = M + M - 1;
    while (l != 1) {
        l /= 2;
        r /= 2;
        for (int i = l; i <= r; ++i) {
            cnt[i][white] = cnt[2 * i][white] + cnt[2 * i + 1][white];
        }
    }
}

void SegmentTree::paint(int ver, int color) {
    switch (color) {
    case YELLOW:
        cnt[ver][yellow] += cnt[ver][white];
        cnt[ver][white] = 0;

        cnt[ver][green] += cnt[ver][blue];
        cnt[ver][blue] = 0;

        red[ver] = cnt[ver][yellow] == 0 && cnt[ver][green] == 0;
        break;
    case BLUE:
        cnt[ver][blue] += cnt[ver][white];
        cnt[ver][white] = 0;

        cnt[ver][green] += cnt[ver][yellow];
        cnt[ver][yellow] = 0;
        red[ver] = cnt[ver][blue] == 0 && cnt[ver][green] == 0;

        break;
    case RED:
        cnt[ver][green] = cnt[ver][blue] = cnt[ver][yellow] = cnt[ver][white] = 0;
        red[ver] = true;

        break;
    }

    last_paint[ver].insert(color);
}

// inserts into [L, R] that intersects with [l, r].
// Is in vertex ver which has range of [l, r].
// [0, M - 1]
tuple<int, int, int, int> SegmentTree::r_insert(int L, int R, int l, int r, int ver, int color) {
    if (l <= R && L <= r) {
        if (L <= l && r <= R) {
            if (!red[ver])
                paint(ver, color);
        } else if (l != r) {
            // l < L || R < r

            if (!last_paint[ver].empty()) {
                if (!red[2 * ver]) {
                    for (auto &i : last_paint[ver])
                        paint(2 * ver, i);
                }
                if (!red[2 * ver + 1]) {
                    for (auto &i : last_paint[ver])
                        paint(2 * ver + 1, i);
                }
                last_paint[ver].clear();
            }

            int m = (static_cast<long>(l) + r) / 2;
            tuple<int, int, int, int> left {0, 0, 0, 0}, right {0, 0, 0, 0};
            if (!red[2 * ver])
                left = r_insert(L, R, l, m, 2 * ver, color);
            if (!red[2 * ver + 1])
                right = r_insert(L, R, m + 1, r, 2 * ver + 1, color);

            cnt[ver][white] = get<0>(left) + get<0>(right);
            cnt[ver][yellow] = get<1>(left) + get<1>(right);
            cnt[ver][blue] = get<2>(left) + get<2>(right);
            cnt[ver][green] = get<3>(left) + get<3>(right);
        }
    }

    return {cnt[ver][white], cnt[ver][yellow], cnt[ver][blue], cnt[ver][green]};
}

void SegmentTree::insert(int l, int r, int color) {
    r_insert(l, r, 0, M - 1, ROOT_ID, color);
}

// query from [L, R] that intersects with [l, r].
// Is in vertex ver which has range of [l, r].
int SegmentTree::r_query(int L, int R, int l, int r, int ver) {
    if (l <= R && L <= r) {
        if (L <= l && r <= R) {
            return cnt[ver][green];
        } else if (l != r) {
            // l < L || R < r

            if (!last_paint[ver].empty()) {
                for (auto &i : last_paint[ver]) {
                    paint(2 * ver, i);
                    paint(2 * ver + 1, i);
                }
                last_paint[ver].clear();
            }

            int m = (static_cast<long>(l) + r) / 2;
            return r_query(L, R, l, m, 2 * ver) +
                   r_query(L, R, m + 1, r, 2 * ver + 1);
        }
    }

    return 0;
}

int SegmentTree::query(int l, int r) {
    return r_query(l, r, 0, M - 1, ROOT_ID);
}

void kol() {
    int n, updates;
    cin >> n >> updates;
    SegmentTree t(n);

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

        t.insert(l - 1, r - 1, c);
    }

    cout << t.query(0, n - 1) << endl;
}

int main() {
    ios_base::sync_with_stdio(false), cin.tie(nullptr);
    kol();
    return 0;
}