#include <bits/stdc++.h>
using namespace std;
const int MAXN = 10;
int gridMAXNMAXN;
int dpMAXNMAXNMAXNMAXN;
int main(){
int n;
cin >> n;
int x, y, num;
while(true){
cin >> x >> y >> num;
if(x == 0 && y == 0 && num == 0)
break;
gridxy = num;
}
for(int x1 = 1; x1 <= n; x1++){
for(int y1 = 1; y1 <= n; y1++){
for(int x2 = 1; x2 <= n; x2++){
int y2 = x1 + y1 - x2;
if(y2 < 1 || y2 >n)
continue;
dpx1y1x2y2 = max({
dpx1 - 1y1x2 - 1y2,//下下
dpx1 - 1y1x2y2 - 1,//下右
dpx1y1 - 1x2 - 1y2,//右下
dpx1y1 - 1x2y2 - 1,//右右
});
if(x1 == x2 && y1 == y2){
dpx1y1x2y2 += gridx1y1;
}else{
dpx1y1x2y2 += gridx1y1 + gridx2y2;
}
}
}
}
cout << dpnnnn << endl;
return 0;
}