// Problem: C. Thief Masters
// Contest: undefined - NOIP2024训练赛 04
// URL: http://www.noi.ac/contest/1156/problem/2406
// Memory Limit: 1024 MB
// Time Limit: 1000 ms
// 
// Powered by CP Editor (https://cpeditor.org)

#include <bits/stdc++.h>

using namespace std;

// #define int long long
// #define x first
// #define y second
#define File(a) freopen(a".in", "r", stdin), freopen(a".out", "w", stdout)

inline void debug() { cerr << '\n'; }
template<typename Type, typename... Other>
inline void debug(const Type& x, const Other&... y) { cerr << x << ' '; debug(y...); }
#define DEBUG(a...) cerr << "[" << #a << "] = ", debug(a);

typedef long long LL;
typedef pair<int, int> PII;

const int N = 2010;
const int INF = 0x3f3f3f3f;

template<typename Type>
inline void read(Type &res)
{
    res = 0;
    int ch = getchar(), flag = 0;
    while (!isdigit(ch)) flag |= ch == '-', ch = getchar();
    while (isdigit(ch)) res = (res << 3) + (res << 1) + (ch ^ 48), ch = getchar();
    res = flag ? -res : res;
}
template<typename Type, typename... Other>
inline void read(Type &res, Other&... y) { read(res), read(y...); }

int n, m, r, c;
int a[N][N], f[N][N], f2[N][N], ans[N][N];
    // f[i][j] = \max { f[i][j], f[i + 1][j] ... f[i + r - 1][j] }
    // ans[i][j] = \max { ans[i][j], ans[i][j + 1], ans[i][j + 2] ... ans[i][j + r - 1]; }
int que[N], hh = 0, tt = -1;
int que2[N], hh2 = 0, tt2 = -1;

signed main()
{
    read(n, m, r); 
    for (int i = 1; i <= n; i ++)
        for (int j = 1; j <= m; j ++) read(a[i][j]);
    
    for (int j = 1; j <= m; j ++)
    {
        hh = 0, tt = -1;
        for (int i = 1; i <= n; i ++)
        {
            while (hh <= tt && i - que[hh] >= r) hh ++;
            while (hh <= tt && a[que[tt]][j] <= a[i][j]) tt --;
            que[++ tt] = i;
            if (i >= r) f[i - r + 1][j] = a[que[hh]][j];
        }
    }
    for (int j = 1; j <= m; j ++)
    {
        hh2 = 0, tt2 = -1;
        for (int i = 1; i <= n; i ++)
        {
            while (hh2 <= tt2 && i - que2[hh2] >= r) hh2 ++;
            while (hh2 <= tt2 && a[que2[tt2]][j] >= a[i][j]) tt2 --;
            que2[++ tt2] = i;
            if (i >= r) f2[i - r + 1][j] = a[que2[hh2]][j];
        }
    }
    for (int i = 1; i <= n; i ++)
    {
        hh = 0, tt = -1;
        for (int j = 1; j <= m; j ++)
        {
            while (hh <= tt && j - que[hh] >= r) hh ++;
            while (hh <= tt && f[i][que[tt]] <= f[i][j]) tt --;
            que[++ tt] = j;
            if (j >= r) ans[i][j - r + 1] = f[i][que[hh]];
        }
    }
	 for (int i = 1; i <= n; i ++)
    {
        hh2 = 0, tt2 = -1;
        for (int j = 1; j <= m; j ++)
        {
            while (hh2 <= tt2 && j - que2[hh2] >= r) hh2 ++;
            while (hh2 <= tt2 && f2[i][que2[tt2]] >= f2[i][j]) tt2 --;
            que2[++ tt2] = j;
            if (j >= r) ans[i][j - r + 1] = abs(ans[i][j - r + 1] - f2[i][que2[hh2]]);
        }
    }
    int res = INF;
    for (int i = 1; i <= n - r + 1; i ++)
        for (int j = 1; j <= m - r + 1; j ++) res = min(res, ans[i][j]);
    // for(int i = 1; i <= n - r + 1; i ++)
    // {
    	// for(int j = 1; j <= m - r + 1; j ++) cout << ans[i][j] << ' ';
    	// cout << '\n';
    // }
    cout << res << '\n';
    return 0;
}