#include <bits/stdc++.h>

using namespace std;
//Jakub Bronowski, III LO Gdynia, PA 2020 Runda 1
//Zadanie Mieszanie Kolorow [B]

int instr[1000010][4] = {0};
int ans1 = 0, ans2 = 0, ans3 = 0;
int n,m, result = 0;
int main()
{
    scanf("%d %d", &n, &m);
    for(int i=0; i<m; ++i)
    {
        int a,b,c;
        scanf("%d%d%d", &a, &b, &c);
        ++instr[a][c];
        --instr[b+1][c];
    }
    for(int i=1; i<=n; ++i)
    {
        ans1 += instr[i][1];
        ans2 += instr[i][2];
        ans3 += instr[i][3];
        if(ans1 > 0 && ans2 > 0 && ans3 < 1 ) ++result;
    }
    printf("%d", result);
    return 0;
}