include[HTML_REMOVED]

include[HTML_REMOVED]

using namespace std;
const int N = 11;
int dp[2*N][N][N];
int w[N][N];

int main()
{
int n;
cin>>n;

int a,b,c;
while(cin>>a>>b>>c, a || b || c)
{
    w[a][b] = c;
}

for(int k = 2; k <= n+n ; k++)
    for(int i1 = 1; i1 <= n ; i1++)
        for(int i2 = 1; i2 <= n; i2++)
        {
            int j1 = k - i1, j2 = k - i2;
            if(j1 >= 1 && j2 >= 1 && j1 <= n && j2 <= n)
            {
                int &x = dp[k][i1][i2];
                int t = w[i1][j1];
                if(i1 != i2) t += w[i2][j2];

                x = max(x, dp[k-1][i1-1][i2-1] + t);
                x = max(x, dp[k-1][i1][i2-1] + t);
                x = max(x, dp[k-1][i1-1][i2]+ t);
                x = max(x,dp[k-1][i1][i2]+t);
            }
        }
cout<<dp[n+n][n][n];

return 0;

}