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#include <bits/stdc++.h>
using namespace std;

const int TREE_SIZE = 1<<20;
set <int> tree[2*TREE_SIZE];

void update(int l, int r, int v)
{
	l += TREE_SIZE - 1; r += TREE_SIZE + 1;
	while(l>>1 != r>>1)
	{
		if((l&1) == 0) tree[l+1].insert(v);
		if((r&1) == 1) tree[r-1].insert(v);
		l>>=1; r>>=1;
	}
}
set <int> query(int x)
{
	x += TREE_SIZE;
	set <int> r;
	while(x) 
	{
		if(!tree[x].empty()) r.insert(tree[x].begin(),tree[x].end());
		x>>=1;
	}
	return r;
}
bool czy(int x)
{
	auto s = query(x);
	return s.size() == 2 && s.count(1) && s.count(2);
}

int main()
{
	ios_base::sync_with_stdio(false);
	int n, m; cin >> n >> m;
	while(m--)
	{
		int l, r, k; cin >> l >> r >> k;
		update(l,r,k);
	}
	int ans = 0;
	for(int i = 1; i <= n; i++)
		ans += czy(i);
	cout << ans;
	return 0;
}