#include <iostream>
#include <vector>
#include <fstream>
using namespace std;

vector < int > add[300];
vector < int > del[300];
int n, m;

void scan(){
    cin >> n >> m;

    for ( int i = 0; i < m; ++i ){
        int c, x, y;

        cin >> c >> x >> y;
        add[x].push_back ( c );
        del[y].push_back ( c );
    }
}

void solve(){
    int cnt = 0, mx = 0;
    for ( int i = 1; i <= n; ++i ){
        for ( int j = 0; j < del[i].size(); ++j )
            cnt -= del[i][j];
        for ( int j = 0; j < add[i].size(); ++j )
            cnt += add[i][j];
        mx = max ( mx, cnt );
    }

    cout << ( mx / 64 ) + (bool)( mx % 64 ) << endl;
}
int main(){
    freopen ( "bdz.in", "r", stdin );
    freopen ( "bdz.out", "w", stdout );
    scan();
    solve();
}