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#include<cstdio>
#include<iostream>
#include<algorithm>
#include<string>
#include<vector>
#include<cmath>
#include<unordered_map>

using namespace std;

typedef vector<int> VI;
typedef long long LL;

#define FOR(x, b, e) for(int x=b; x<=(e); ++x)
#define FORD(x, b, e) for(int x=b; x>=(e); --x)
#define REP(x, n) for(int x=0; x<(n); ++x)
#define VAR(v, n) __typeof(n) v = (n)
#define ALL(c) (c).begin(), (c).end()
#define SIZE(x) ((int)(x).size())
#define FOREACH(i, c) for(VAR(i, (c).begin()); i != (c).end(); ++i)
#define PB push_back
#define ST first
#define ND second

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

struct ColoursTree {
    unordered_map<int, int> el;
    int s = 1 << 21;

    void add(int p, int k, int c) {
        int m = 0;
        p += s; k += s;
        while(p < k) {
            if(p & 1) el[p++] |= c;
            if(!(k & 1)) el[k--] |= c;
            p >>= 1;
            k >>= 1;
        }
        if(p == k) el[p] |= c;
    }

    int get(int p) {
        int res = 0;
        for(p += s; p; p >>= 1) res |= el[p];
        return res;
    }
};

int main() {
	ios_base::sync_with_stdio(0);
    int n, m;
    cin >> n >> m;
    ColoursTree tree;
    REP(i, m) {
        int l, r, k;
        cin >> l >> r >> k;
        tree.add(l, r, 1 << --k);
    }
    int green = 1 + 2;
    int count = 0;
    REP(i, n) {
        //cout << i+1 << ": " << tree.get(i+1) << '\n';
        if(tree.get(i+1) == green) count++;
    }
    //cout << tree.get(n) << '\n';
    cout << count << '\n';
    return 0;
}