1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
#include <bits/stdc++.h>
#include <math.h>
using namespace std;
#define endl "\n"
#define mp make_pair
#define st first
#define nd second
#define pii pair<int, int>
#define pb push_back
#define _upgrade ios_base::sync_with_stdio(0), cout.setf(ios::fixed), cout.precision(10), cin.tie(0), cout.tie(0);
#define REP(i, n) for (int i = 0; i < (n); ++i)
#define FWD(i, a, b) for (int i = (a); i < (b); ++i)
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define fwd(i, a, b) for (int i = (a); i < (b); ++i)
#define all(c) (c).begin(), (c).end()
#define sz(X) (int)((X).size())
#define what(x) cerr << #x << " is " << x << endl;

ostream &operator<<(ostream &out, string str) {
   for (char c : str)
      out << c;
   return out;
}
template <class L, class R> ostream &operator<<(ostream &out, pair<L, R> p) { return out << "(" << p.st << ", " << p.nd << ")"; }
template <class T> auto operator<<(ostream &out, T a) -> decltype(a.begin(), out) {
   out << '{';
   for (auto it = a.begin(); it != a.end(); it = next(it))
      out << (it != a.begin() ? ", " : "") << *it;
   return out << '}';
}
void dump() { cerr << "\n"; }
template <class T, class... Ts> void dump(T a, Ts... x) {
   cerr << a << ", ";
   dump(x...);
}
#define debug(...) cerr << "[" #__VA_ARGS__ "]: ", dump(__VA_ARGS__)

const int MAXN = 1e6 + 99;
vector<int> add[MAXN];
vector<int> sub[MAXN];
int counter[3];
int n, m;

bool zielona() { return counter[0] > 0 && counter[1] > 0 && counter[2] == 0; }
int32_t main() {
   _upgrade;
   cin >> n >> m;
   rep(i, m) {
      int a, b, c;
      cin >> a >> b >> c;
      --a, --c;
      add[a].push_back(c);
      sub[b].push_back(c);
   }
   int res = 0;
   rep(i, n) {
      for (int a : add[i])
         counter[a]++;
      for (int b : sub[i])
         counter[b]--;
      if (zielona())
         res++;
   }
   cout << res << endl;
}