#include <bits/stdc++.h>
#define int long long
using namespace std;
int n, m, k, a[1001][1001], q[1001], h = 1, t, ans = INT_MAX, r[1001][1001], l[1001][1001], maxn[1001], minn[1001], maxx[1001], minx[1001];
void work(int a[], int ans[], int len, bool flag)
{
	int x,y;
    h = 1, t = 0;
    for (int i = 1; i <= len; 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("%lld %lld %lld", &n, &m, &k);
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++)
            scanf("%lld", &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("%lld", ans);
    return 0;
}