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

#define INF (1000000000)
#define MAXM (1000 + 100)
#define MAXN (100 + 10)
#define MAXLOG (10)

int a, b, n;
int logn, ans;
int grid[MAXM][MAXM];
int maxv[MAXM][MAXM], minv[MAXM][MAXM];

int query(int x, int y)
{
  int _max = 0, _min = 0;
  _max = max(maxv[x][y], max(maxv[x + n - (1 << logn)][y + n - (1 << logn)], max(maxv[x + n - (1 << logn)][y], maxv[x][y + n - (1 << logn)])));
  _min = min(minv[x][y], min(minv[x + n - (1 << logn)][y + n - (1 << logn)], min(minv[x + n - (1 << logn)][y], minv[x][y + n - (1 << logn)])));
  return _max - _min;
}

int main()
{
#ifdef HERITAGE_OFFICIAL
  freopen("_data.in", "r", stdin);
  // freopen("_data.out", "w", stdout);
#endif
  cin >> a >> b >> n;
  for (int i = 0; i < a; i++)
    for (int j = 0; j < b; j++)
    {
      scanf("%d", &grid[i][j]);
      maxv[i][j] = minv[i][j] = grid[i][j];
    }
  for (logn = 0; ((1 << (logn + 1)) <= n); logn++)
    ;
  for (int k = 0; k < logn; k++)
    for (int i = 0; i + (1 << k) < a; i++)
      for (int j = 0; j + (1 << k) < b; j++)
      {
        maxv[i][j] = max(maxv[i][j], max(maxv[i + (1 << k)][j + (1 << k)], max(maxv[i + (1 << k)][j], maxv[i][j + (1 << k)])));
        minv[i][j] = min(minv[i][j], min(minv[i + (1 << k)][j + (1 << k)], min(minv[i + (1 << k)][j], minv[i][j + (1 << k)])));
      }

  ans = INF;
  for (int i = 0; i <= a - n; i++)
    for (int j = 0; j <= b - n; j++)
      ans = min(ans, query(i, j));

  cout << ans;
  fclose(stdin);
  return 0;
}