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#include <iostream>
#include <vector>
#include <tuple>

using namespace std;

/*int comb(int a, int b){
  if(a > b){
    swap(a,b);
  }

  if(a == 0){
    return b;
  } else if(a == 1){
    if(b == 1){
      return 1;
    } else if(b == 2 || b==4){
      return 4;
    } else if(b== 3 || b==5){
      return 5;
    } else {
      return 7;
    }
  } else if(a==2){
    if(b == 2){
      return 2;
    } else if(b== 3 || b==6){
      return 6;
    } else {
      return 7;
    }
  } else if(a==3) {
    if(b == 5 || b == 6){
      return b;
    }
  }
}*/

int main(){
  int n, m;
  cin >> n >> m;

  vector<tuple<int,int,int>> Q(n, make_tuple(0, 0, 0));
  while(m--){
    int l, r, k;
    cin >> l >> r >> k;

    if(k-1 == 0){
      get<0>(Q[l-1]) = 1;
      get<0>(Q[r-1]) = -1;
    }
    if(k-1 == 1){
      get<1>(Q[l-1]) = 1;
      get<1>(Q[r-1]) = -1;
    }
    if(k-1 == 2){
      get<2>(Q[l-1]) = 1;
      get<2>(Q[r-1]) = -1;
    }
  }

  int res = 0;
  tuple<int,int,int> temp = make_tuple(0,0,0);
  for(int i = 0; i < Q.size(); i++){
    get<0>(temp) += get<0>(Q[i]);
    get<1>(temp) += get<1>(Q[i]);
    get<2>(temp) += get<2>(Q[i]);
    if(get<0>(temp) > 0 && get<1>(temp) > 0 && get<2>(temp) == 0){
      res++;
    }
  }

  cout << res << endl;
}