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#include <bits/stdc++.h>
using namespace std;
#define PII pair<int, int>
#define VI vector<int>
#define VPII vector<PII>
#define LL long long
#define LD long double
#define f first
#define s second
#define MP make_pair
#define PB push_back
#define endl '\n'      // UWAGA
#define ALL(c) (c).begin(), (c).end()
#define SIZ(c) (int)(c).size()
#define REP(i, n) for(int i = 0; i < (int)(n); ++i)
#define FOR(i, b, e) for(int i = (b); i <= (int)(e); ++i)
#define FORD(i, b, e) for(int i = (b); i >= (int)(e); --i)
#define random_shuffle(V) shuffle(V, rng)

#define sim template<class n
sim, class s> ostream & operator << (ostream &p, pair<n, s> x)
{return p << "<" << x.f << ", " << x.s << ">";}
sim> auto operator << (ostream &p, n y) ->
typename enable_if<!is_same<n, string>::value, decltype(y.begin(), p)>::type 
{int o = 0; p << "{"; for(auto c: y) {if(o++) p << ", "; p << c;} return p << "}";}
void dor() {cerr << endl;}
sim, class...s> void dor(n p, s...y) {cerr << p << " "; dor(y...);}
sim, class s> void mini(n &p, s y) {if(p>y) p = y;}
sim, class s> void maxi(n &p, s y) {if(p<y) p = y;}
#ifdef DEB
#define debug(...) dor(__FUNCTION__, ":", __LINE__, ": ", __VA_ARGS__)
#else
#define debug(...)
#endif 

#define I(x) #x " =", (x), " "
#define A(a, i) #a "[" #i " =", i, "] =", a[i], " "

const int MXN = 1e6+6;
int state[3][MXN];

int main()
  {
  int n, m;
  scanf("%d%d", &n, &m);
  REP(i, m)
    {
    int a, b, k;
    scanf("%d%d%d", &a, &b, &k);
    state[k-1][a]++;
    state[k-1][b+1]--;
    }
  int res = 0;
  FOR(i, 1, n)
    {
    REP(j, 3)
      state[j][i] += state[j][i-1];
    if(state[0][i] && state[1][i] && state[2][i] == 0)res++;
    }
  printf("%d\n", res);
  }