#include<bits/stdc++.h>
#define ll long long
using namespace std;
const ll N=3e2+10;
ll read(){
	ll x=0,sgn=1;char ch=getchar();
	while(ch>'9'||ch<'0'){if(ch=='-')sgn*=-1;ch=getchar();}
	while(ch>='0'&&ch<='9'){x=(x<<3)+(x<<1)+(ch&15);ch=getchar();}
	return x*sgn; 
} 
ll n,m;
ll w[N],L[N],R[N];
ll p[N][N][N],dp[N][N];
int main(){
	n=read();m=read();
	for(int i=1;i<=m;i++){
		w[i]=read();L[i]=read();R[i]=read();
		for(int j=L[i];j<=R[i];j++){
			p[j][L[i]][R[i]]=max(p[j][L[i]][R[i]],w[i]);
		}
	}
	for(int k=1;k<=n;k++){
		for(int l=k;l>=1;l--){
			for(int r=k;r<=n;r++){
				if(l-1>=1)p[k][l-1][r]=max(p[k][l-1][r],p[k][l][r]);
				if(r+1<=n)p[k][l][r+1]=max(p[k][l][r+1],p[k][l][r]);
			}
		}
	}
	for(int i=1;i<=n;i++){
		dp[i][i]=max(dp[i][i],p[i][i][i]);
	}
	for(int s=2;s<=n;s++){
		for(int l=1;l<=n&&l+s-1<=n;l++){
			int r=l+s-1;
			for(int k=l;k<=r;k++){
				dp[l][r]=max(dp[l][r],dp[l][k-1]+dp[k+1][r]+p[k][l][r]);
			}
		}
	}
	cout<<dp[1][n];
	return 0;
}