#include <fstream>
using namespace std;
ifstream f("inundatii.in");
ofstream g("inundatii.out");
long long i, n,x,y,z,S;
int main()
{f>>n;
if(n==1)
g<<"0\n";
for(i=1;i<=n/2;i++){
f>>x>>y>>z;
S=S+x+y+z;
}
f>>x>>y>>z;
if(n%2==0)
S-=(x+y+z);
for(i=n/2+2;i<=n;i++){
f>>x>>y>>z;
S-=(x+y+z);}
if(n%2)
S+=3*(n/2)*(n/2+1);
else
S+=3*(n*n/4);
g<<S<<'\n';
return 0;
}