#include<bits/stdc++.h>
#define int long long
using namespace std;
const int N=1e6+10;
int n,m,x,y,z,r[N],ans;
signed main(){
	cin>>n>>m;
	while(m--){
		cin>>x>>y>>z;
		if(x<=y) r[x]+=z,r[y+1]-=z;
		else{
			r[x]+=z;
			r[1]+=z,r[y+1]-=z;
		}
	}
	for(int i=1;i<=n;i++) r[i]+=r[i-1];
	for(int i=1;i<=n;i++){
		ans=max(ans,r[i]);
	}
	cout<<(ans+35)/36;
	return 0;
}