#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<iostream>
#define Max(a,b,c,d) max(max(a,b),max(c,d))
using namespace std;
 
int read()
{
	int x=0,f=1;char ch=getchar();
	while(ch<'0' ||ch>'9'){
		if(ch=='-') f=-1;
		ch=getchar();
	}
	while(ch<='9'&&ch>='0'){
		x=x*10+ch-48;
		ch=getchar();
	}
	return x*f;
}
int map[11][11],f[11][11][11][11];
int main()
{
	freopen("fgqs.in","r",stdin);
	freopen("fgqs.out","w",stdout);
	int n=read();int x,y,c;
	while(scanf("%d",&x)&&x){
		scanf("%d%d",&y,&c);
		map[x][y]=c;
	}
	for(int i=1;i<=n;i++)
		for(int j=1;j<=n;j++)
			for(int s=1;s<=n;s++)
				for(int t=1;t<=n;t++){
					int l=max(max(max(f[i-1][j][s-1][t],f[i-1][j][s][t-1]),f[i][j-1][s-1][t]),f[i][j-1][s][t-1]);
					f[i][j][s][t]=l+map[i][j];
					if(i!=s||j!=t) f[i][j][s][t]+=map[s][t];
				}
	printf("%d",f[n][n][n][n]);
	return 0;
}