#include <bits/stdc++.h>
#define int long long
using namespace std;
int n, m, k, ans = INT_MAX, shark[1005], a[1005][1005], maxn[1005][1005], minn[1005][1005], mas[1005][1005], xmas[1005][1005];
signed main()
{
#ifndef ONLINE_JUDGE
  freopen("data/data.in", "r", stdin);
// freopen("data/data.out", "w", stdout);
#endif
  std::ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
  cin >> n >> m >> k;
  for (int i = 1; i <= n; i++)
    for (int j = 1; j <= m; j++)
      cin >> a[i][j];
  for (int i = 1; i <= n; i++)
  {
    deque<int> q;
    for (int j = 1; j <= m; j++)
    {
      if (q.size() && q.front() < j - k + 1)
        q.pop_front();
      while (q.size() && a[i][q.back()] >= a[i][j])
        q.pop_back();
      q.push_back(j);
      minn[i][j] = a[i][q.front()];
    }
    while (q.size())
      q.pop_back();
    for (int j = 1; j <= m; j++)
    {
      if (q.size() && q.front() < j - k + 1)
        q.pop_front();
      while (q.size() && a[i][q.back()] <= a[i][j])
        q.pop_back();
      q.push_back(j);
      maxn[i][j] = a[i][q.front()];
    }
  }
  for (int i = 1; i <= m; i++)
  {
    deque<int> q;
    for (int j = 1; j <= n; j++)
    {
      if (q.size() && q.front() < j - k + 1)
        q.pop_front();
      while (q.size() && minn[q.back()][i] >= minn[j][i])
        q.pop_back();
      q.push_back(j);
      mas[j][i] = minn[q.front()][i];
    }
    while (q.size())
      q.pop_back();
    for (int j = 1; j <= n; j++)
    {
      if (q.size() && q.front() < j - k + 1)
        q.pop_front();
      while (q.size() && maxn[q.back()][i] <= maxn[j][i])
        q.pop_back();
      q.push_back(j);
      xmas[j][i] = maxn[q.front()][i];
    }
  }
  for (int i = k; i <= n; i++)
    for (int j = k; j <= m; j++)
      ans = min(ans, xmas[i][j] - mas[i][j]);
  cout << ans;
  exit(0);
}