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

#define FOR(i, a, b) for(int i = (a); i <= (b); ++i)
#define REP(i, n) for(int i = 0; i < (n); ++i)
#define ff first
#define ss second

using ll = long long;
using pii = pair<int, int>;

template<class T> int size(T && a) {
	return (int)(a.size());
}
ostream& operator << (ostream &os, string str) {
    for(char c : str) os << c;
    return os;
}
template <class A, class B> ostream& operator << (ostream &os, const pair<A, B> &p) {
	return os << '(' << p.ff << "," << p.ss << ')';
}
template <class T> auto operator << (ostream &os, T &&x) -> decltype(x.begin(), os) {
	os << '{';
	for(auto it = x.begin(); it != x.end(); ++it)
		os << *it << (it == prev(x.end()) ? "" : " ");
	return os << '}';
}
template <class T> ostream& operator << (ostream &os, vector<vector<T>> vec) {
    for(auto x : vec)
    	os << "\n  " << x;
    return os;
}
void dump() {}
template <class T, class... Args> void dump(T &&x, Args... args) {
    cerr << x << "; ";
    dump(args...);
}
#ifdef DEBUG
# define debug(x...) cerr << "[" #x "]: ", dump(x), cerr << '\n'
#else 
# define debug(...) 0
#endif

//--------------------------------------------------

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);

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

	vector<array<int, 3>> sum(n+1, {0, 0, 0});
	while(m--) {
		int l, r, k;
		cin >> l >> r >> k;
		--l, --r, --k;

		sum[l][k]++;
		sum[r+1][k]--;
	}

	int ans = 0;
	REP(i, n) {
		if(i > 0)
			REP(k, 3) sum[i][k] += sum[i-1][k];
		if(sum[i][0] and sum[i][1] and !sum[i][2])
			++ans;
	}

	cout << ans << '\n';
}