#include <bits/stdc++.h>
#define MX 20
using namespace std;
int x;
struct m
{
	int x,y;
	int num;
};
m a[MX * MX + 10];
bool cmp(m p,m q)
{
	return p.num > q.num;
}
int main()
{
	int m,n,k;
	int cnt = 0;
	cin >> m >> n >> k;
	int i,j;
	for(i = 1;i <= n;i++)
	{
		for(j = 1;j <= m;j++)
		{
			cin >> x;
			cnt++;
			a[cnt].num = x;
			a[cnt].x = i;
			a[cnt].y = j;
		}
    }
	sort(a + 1,a + cnt + 1,cmp);
	int sum = 0;
	int t = 1 + abs(a[1].x - a[2].x) + abs(a[1].y - a[2].y);
	sum = sum + a[1].num;
	for(i = 2;i <= cnt;i++)
	{
		t = t + 1 + abs(a[i - 1].x - a[i].x) + abs(a[i - 1].y - a[i].y);
		if(t < k)
		{
			sum = sum + a[i].num;
		}
	}
	cout << sum << endl;
	return 0;
}