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#include <bits/stdc++.h>

#define FOR(i, b, e) for (int i = (b); i <= (e); i++)
#define FORD(i, b, e) for (int i = (e); i >= (b); i--)
#define MP make_pair
#define FS first
#define ND second
#define PB push_back
#define ALL(x) x.begin(), x.end()

using namespace std;

using LL = long long;
using PII = pair<int,int>;
using PLL = pair<LL,LL>;
using VI = vector<int>;
using VLL = vector<LL>;

template<class T>
int sz(const T& a) { return (int)a.size(); }
template<class T>
void amin(T& a, T b) { a = min(a, b); }
template<class T>
void amax(T& a, T b) { a = max(a, b); }

const int inf = 1e9;
const LL infl = 1e18;

int n, m, ans;
int a[int(1e6) + 1], cnt[3][int(1e6) + 2];

int main()
{
  scanf("%d %d", &n, &m);
  FOR(i, 1, m) {
    int l, r, k;
    scanf("%d %d %d", &l, &r, &k);
    cnt[k - 1][l]++;
    cnt[k - 1][r + 1]--;
  }

  FOR(k, 0, 2) {
    int s = 0;
    FOR(i, 1, n) {
      s += cnt[k][i];
      a[i] |= (s > 0) * (1 << k);
    }
  }

  FOR(i, 1, n) ans += (a[i] == 3);
  printf("%d\n", ans);
}