#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>using namespace std;const int MaxN = 1000 + 5, INF = 999999999;int a, b, n, Ans;
int Map[MaxN][MaxN], Q[MaxN][MaxN], F[MaxN], Head[MaxN], Tail[MaxN], Min[MaxN][MaxN], Max[MaxN][MaxN];
//Q[0]是纵向的单调队列 inline int gmin(int a, int b) {return a < b ? a : b;}
inline int gmax(int a, int b) {return a > b ? a : b;}void Get_Min()
{for (int i = 1; i <= a; ++i) {Head[i] = 1;Tail[i] = 0;}for (int i = 1; i <= b; ++i) {for (int j = 1; j <= a; ++j) {if (i > n && Head[j] <= Tail[j] && Q[j][Head[j]] == i - n) ++Head[j];while (Head[j] <= Tail[j] && Map[j][i] < Map[j][Q[j][Tail[j]]]) --Tail[j];Q[j][++Tail[j]] = i; }   if (i >= n) {Head[0] = 1; Tail[0] = 0;for (int j = 1; j <= a; ++j){F[j] = Map[j][Q[j][Head[j]]];if (j > n && Head[0] <= Tail[0] && Q[0][Head[0]] == j - n) ++Head[0];while (Head[0] <= Tail[0] && F[j] < F[Q[0][Tail[0]]]) --Tail[0];Q[0][++Tail[0]] = j;if (j >= n) Min[j][i] = F[Q[0][Head[0]]]; }}}
}void Get_Max()
{for (int i = 1; i <= a; ++i) {Head[i] = 1;Tail[i] = 0;}for (int i = 1; i <= b; ++i) {for (int j = 1; j <= a; ++j) {if (i > n && Head[j] <= Tail[j] && Q[j][Head[j]] == i - n) ++Head[j];while (Head[j] <= Tail[j] && Map[j][i] > Map[j][Q[j][Tail[j]]]) --Tail[j];Q[j][++Tail[j]] = i; }if (i >= n) {Head[0] = 1; Tail[0] = 0;for (int j = 1; j <= a; ++j){F[j] = Map[j][Q[j][Head[j]]];if (j > n && Head[0] <= Tail[0] && Q[0][Head[0]] == j - n) ++Head[0];while (Head[0] <= Tail[0] && F[j] > F[Q[0][Tail[0]]]) --Tail[0];Q[0][++Tail[0]] = j;if (j >= n) Max[j][i] = F[Q[0][Head[0]]]; }}}
}int main()
{scanf("%d%d%d", &a, &b, &n);for (int i = 1; i <= a; ++i) for (int j = 1; j <= b; ++j) scanf("%d", &Map[i][j]);Get_Min();Get_Max();Ans = INF;for (int i = n; i <= a; ++i) for (int j = n; j <= b; ++j) Ans = gmin(Ans, Max[i][j] - Min[i][j]);printf("%d\n", Ans);return 0;
}