#include <iostream>
using namespace std;
long long st[1000010],fi[1000010],r[1000010],n,m,cha[1000010],s,he,g,sh=36;
int main(){
	cin>>n>>m;
	for (int i=1;i<=m;i++){
		cin>>st[i]>>fi[i]>>r[i];
		cha[i]=st[i]-fi[i-1];
	}
	for (int i=1;i<=m;i++){
		g=0;
		if (cha[i]==0){
			if(r[i]>r[i-1]){
				g=r[i];
				g-=r[i-1];
				he+=g/36;
				if (g%36!=0){
					if (sh==36) he++; 
					if (sh-g%36<0){
						he++;
						sh-=g%36;
						sh=36+sh;
					}
					else{
						sh-=g%36;
					}
				}
			}
		}
		else{
			s=r[i]%36;
			he+=r[i]/36;
			if (s!=0){
				if(sh==36) he++;
				if (sh-s<0){
					he++;
					sh-=s;
					sh=36+sh;
				}
				else{
					sh-=s;
				}
			}
		}
	}
	cout<<he;
	return 0;
}