#include <iostream>

int main(){
    long int containers, size;
    long int beg, end, temp;
    short color;

    temp = 0;

    std::cin >> containers >> size;
    int *str = new int[containers];

    for(int i = 0; i < containers; i++)
        str[i] = 0;

    while(size--){
        std::cin >> beg >> end >> color;

        for(int i = beg-1; i < end; i++){
            str[i] += (color * 10) + 1;
            if(str[i] == 32)
                temp++;
        }
        
    }

    std::cout << temp << std::endl;

    return 0;
}

/*
9 5
2 8 1
4 5 2
6 7 3
5 6 2
1 2 2
*/