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#include<cstdio>

struct Range
{
    int l;
    int r;

    Range() {}
    Range(int l, int r) { this->l = l; this->r = r; }
};

class PQ
{
    bool compare(const int pos1, const int pos2)
    {
        if (entries[pos1].l < entries[pos2].l) return true;
        if (entries[pos2].l < entries[pos1].l) return false;
        return entries[pos2].r < entries[pos1].r;
    }

    void swap(const int pos1, const int pos2) { Range tmp = entries[pos1]; entries[pos1] = entries[pos2]; entries[pos2] = tmp; }

    void HeapUp(int pos)
    {
        if (pos == 1) return;
        int parent = pos / 2;

        if (compare(pos, parent))
        {
            swap(pos, parent);
            HeapUp(parent);
        }
    }

    void HeapDown(int pos)
    {
        if (count < 2 * pos) return;

        int smaller = 2 * pos;

        if (smaller + 1 <= count && compare(smaller + 1, smaller)) smaller++;

        if (compare(smaller, pos))
        {
            swap(smaller, pos);
            HeapDown(smaller);
        }
    }

public:
    int size;
    int count;
    Range* entries;

    PQ() { this->size = 2; this->count = 0; this->entries = new Range[this->size]; }

    void push(Range range_to_push)
    {
        count++;
        if (count == size)
        {
            size *= 2;
            Range* next = new Range[size];
            for (int i = 1; i < count; ++i) next[i] = entries[i];
            delete[] entries;
            entries = next;
        }
        entries[count] = range_to_push;
        HeapUp(count);
    }

    void push(int l, int r) { push(Range(l, r)); }

    Range pop()
    {
        Range result = entries[1];
        entries[1] = entries[count--];
        HeapDown(1);
        return result;
    }

    bool empty() { return count == 0; }
};

PQ ranges[10];
int n, m, l, r, k;

void merge_ranges(int id)
{
    if (ranges[id].empty()) return;

    Range current_range = ranges[id].pop();
    Range next_range;

    while (!ranges[id].empty())
    {
        next_range = ranges[id].pop();
        if (current_range.r + 1 < next_range.l)
        {
            ranges[id + 3].push(current_range);
            current_range = next_range;
        }
        else current_range.r = current_range.r < next_range.r ? next_range.r : current_range.r;
    }
    ranges[id + 3].push(current_range);
}

void reverse_range(int id1, int id2)
{
    Range current_range;
    int new_l = 1;

    while (!ranges[id1].empty())
    {
        current_range = ranges[id1].pop();
        ranges[id2].push(new_l, current_range.l - 1);
        new_l = current_range.r + 1;
    }

    ranges[id2].push(new_l, n);
}

void intersect_ranges(int id1, int id2, int id3)
{
    if (ranges[id1].empty() || ranges[id2].empty()) return;

    Range current_range1;
    Range current_range2;

    while (!ranges[id1].empty() && !ranges[id2].empty())
    {
        current_range1 = ranges[id1].pop();
        current_range2 = ranges[id2].pop();
        if (current_range1.r < current_range2.l)
        {
            ranges[id2].push(current_range2);
            continue;
        }
        if (current_range2.r < current_range1.l)
        {
            ranges[id1].push(current_range1);
            continue;
        }
        if (current_range1.l < current_range2.l && current_range1.r < current_range2.r)
        {
            ranges[id3].push(current_range2.l, current_range1.r);
            ranges[id2].push(current_range1.r + 1, current_range2.r);
            continue;
        }
        if (current_range2.l <= current_range1.l && current_range1.r < current_range2.r)
        {
            ranges[id3].push(current_range1.l, current_range1.r);
            ranges[id2].push(current_range1.r + 1, current_range2.r);
            continue;
        }
        if (current_range1.l < current_range2.l && current_range2.r <= current_range1.r)
        {
            ranges[id3].push(current_range2.l, current_range2.r);
            if (current_range2.r < current_range1.r) ranges[id1].push(current_range2.r + 1, current_range1.r);
            continue;
        }
        if (current_range2.l <= current_range1.l && current_range2.r <= current_range1.r)
        {
            ranges[id3].push(current_range1.l, current_range2.r);
            if (current_range2.r < current_range1.r) ranges[id1].push(current_range2.r + 1, current_range1.r);
            continue;
        }

    }

}

int main()
{
    scanf("%d%d", &n, &m);
    for (int i = 0; i < m; ++i)
    {
        scanf("%d%d%d", &l, &r, &k);
        ranges[k - 1].push(l, r);
    }

    for (int i = 0; i < 3; ++i) merge_ranges(i);
    reverse_range(5, 6);
    intersect_ranges(3, 4, 7);
    intersect_ranges(6, 7, 8);

    int ans = 0;
    while (!ranges[8].empty())
    {
        Range tmp = ranges[8].pop();
        ans += tmp.r - tmp.l + 1;
    }
    printf("%d\n", ans);
    return 0;
}