#include <bits/stdc++.h>
using namespace std;
int n, m, k, a[5001][5001], q[5001], h = 1, t, ans = INT_MAX, r[5001][5001], l[5001][5001], maxn[5001], minn[5001], maxx[5001], minx[5001];
void work(int a[], int ans[], int n, bool flag)
{
    h = 1, t = 0;
    for (int i = 1; i <= n; i++)
    {
        if (h <= t && q[h] <= i - k)
            h++;
        if(flag)
        {
            while (h <= t && a[i]<=a[q[t]])
                t--;
        }
        else
        {
            while (h <= t && a[i]>=a[q[t]])
                t--;
		}
        q[++t] = i;
        if (i >= k)
            ans[i - k + 1] = a[q[h]];
    }
}
signed main()
{
    scanf("%d %d %d", &n, &m, &k);
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++)
            scanf("%d", &a[i][j]);
    for (int i = 1; i <= n; i++)
    {
        work(a[i], r[i], m , 0);
        work(a[i], l[i], m , 1);
    }
    for (int j = 1; j <= m - k + 1; j++)
    {
        for (int i = 1; i <= n; i++)
            maxn[i] = r[i][j], minn[i] = l[i][j];
        work(maxn, maxx, n, 0);
        work(minn, minx, n, 1);
        for (int i = 1; i <= n - k + 1; i++)
            ans = min(ans, maxx[i] - minx[i]);
    }
    printf("%d", ans);
    return 0;
}