#include <bits/stdc++.h>
using namespace std;

using ll=long long;
#define int ll

#define rng(i, a, b) for(int i=(int)a;i<(int)b;i++)
#define rep(i,n) rng(i,0,n)
using ld=long double;
const ld eps=1e-9;
bool is0(ld x){ return -eps<=x&&x<=eps; }
template<class t>using vc=vector<t>;
template<class t>using vvc=vc<vc<t>>;
using vi=vc<int>;

#define bg begin()
#define ed end()
#define all(x) x.bg,x.ed

void slv(){
	int n;cin>>n;
	vi a(n);
	rep(i,n)rep(j,n){
		int v;cin>>v;
		a[i]+=v;
	}
	sort(all(a));
	int ans=0;
	rep(i,n/2)ans-=a[i];
	rng(i,n/2,n)ans+=a[i];
	cout<<ans/2<<endl;
}

signed main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout<<fixed<<setprecision(20);
	
	slv();
}