#include <cstdio>

#define maxn 1005

int S[maxn][maxn][11], M[maxn][maxn][11];

int n, m, p, K, P;

int LG[maxn], pw[maxn];

inline int max(int a, int b) {return a > b ? a : b;}

inline int min(int a, int b) {return a < b ? a : b;}

inline int getS(int a, int b) {

	int c = a + p, d = b + p;

	int l = max(S[a][b][K], S[c - P][b][K]),

	r = max(S[a][d - P][K], S[c - P][d - P][K]);

	return max(l, r);

}

inline int getM(int a, int b) {

	int c = a + p, d = b + p;

	int l = min(M[a][b][K], M[c - P][b][K]),

	r = min(M[a][d - P][K], M[c - P][d - P][K]);

	return min(l, r);

}

int main() {

	scanf("%d%d%d", &n, &m, &p);

	for (register int i = 1; i <= n; i++) {

		for (register int j = 1; j <= m; j++) scanf("%d", &S[i][j][0]), M[i][j][0] = S[i][j][0];

	}

	LG[0] = -1; for (int i = 1; i < maxn; i++) LG[i] = LG[i >> 1] + 1; K = LG[p];

	pw[0] = 1; for (int i = 1; i < 100; i++) pw[i] = pw[i - 1] * 2ll % 20040826; P = pw[K];

	for (register int k = 1; k < 11; k++) {

		for (register int i = 1; i <= n; i++) {

			for (register int j = 1; j <= m; j++) {

				S[i][j][k] = max(max(S[i][j][k - 1], S[i][min(m, j + pw[k - 1])][k - 1]),

				max(S[min(n, i + pw[k - 1])][j][k - 1], S[min(n, i + pw[k - 1])][min(m, j + pw[k - 1])][k - 1]));

				M[i][j][k] = min(min(M[i][j][k - 1], M[i][min(m, j + pw[k - 1])][k - 1]),

				min(M[min(n, i + pw[k - 1])][j][k - 1], M[min(n, i + pw[k - 1])][min(m, j + pw[k - 1])][k - 1]));

			}

		}

	}

	int ans = 0x3f3f3f3f;

	for (int i = 1; i <= n - p + 1; i++) {

		for (int j = 1; j <= m - p + 1; j++) {

			ans = min(ans, getS(i, j) - getM(i, j));

		}

	}

	printf("%d\n", ans);

	return 0;

}