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#pragma GCC optimize ("O3")
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int, int> ii;
typedef vector<int> vi;
const int INF = 0x3f3f3f3f;

#define FOR(i,b,e) for(int i = (b); i < (e); i++)
#define TRAV(x,a) for(auto &x: (a))
#define SZ(x) ((int)x.size())
#define PB push_back
#define X first
#define Y second

const int N = 1e6+5;

int farb[N][3];

void solve(){
    int n, m, ans = 0;
    cin >> n >> m;
    FOR(i, 0, m){
        int l, r, k;
        cin >> l >> r >> k;
        farb[l][k-1]++;
        farb[r+1][k-1]--;
    }
    FOR(i, 1, n+1) FOR(k, 0, 3) farb[i][k] += farb[i-1][k];
    FOR(i, 1, n+1) ans += farb[i][0] > 0 && farb[i][1] > 0 && farb[i][2] == 0;
    cout << ans << '\n';
}

int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    solve();
    return 0;
}