#include<bits/stdc++.h>
using namespace std;
#define int long long
int m[1010][1010], q[1010];
int rowmin[1010][1010], rowmax[1010][1010];
int colmin[1010][1010], colmax[1010][1010];
int a, b, n, ans = 100000000;
signed main() {
	cin >> a >> b >> n;
	for(int i = 1;i <= a;i ++) {
		for(int j = 1;j <= b;j ++) {
			cin >> m[i][j];
		}
	}
	for(int row = 1;row <= a;row ++) {
		int h = 0, t = 0;
		for(int i = 1;i <= b;i ++) {
			while(h < t && q[h] + n <= i) h ++;
			while(h < t && m[row][q[t - 1]] < m[row][i]) t --;
			q[t] = i;
			t ++;
			if(i >= n) rowmax[row][i - n + 1] = m[row][q[h]];
		}
		h = 0, t = 0;
		for(int i = 1;i <= b;i ++) {
			while(h < t && q[h] + n <= i) h ++;
			while(h < t && m[row][q[t - 1]] > m[row][i]) t --;
			q[t] = i;
			t ++;
			if(i >= n) rowmin[row][i - n + 1] = m[row][q[h]];
		}
	}
	memset(q, 0, sizeof(q));
	for(int col = 1;col <= b - n + 1;col ++) {
		int h = 0, t = 0;
		for(int i = 1;i <= a;i ++) {
			while(h < t && q[h] + n <= i) h ++;
			while(h < t && rowmax[q[t - 1]][col] < rowmax[i][col]) t --;
			q[t] = i;
			t ++;
			if(i >= n) colmax[i - n + 1][col] = rowmax[q[h]][col];
		}
		h = 0, t = 0;
		for(int i = 1;i <= a;i ++) {
			while(h < t && q[h] + n <= i) h ++;
			while(h < t && rowmin[q[t - 1]][col] > rowmin[i][col]) t --;
			q[t] = i;
			t ++;
			if(i >= n) colmin[i - n + 1][col] = rowmin[q[h]][col];
		}
	}
	for(int i = 1;i <= a - n + 1;i ++) {
		for(int j = 1;j <= b - n + 1;j ++) {
			if(colmax[i][j] - colmin[i][j] < ans) {
				ans = colmax[i][j] - colmin[i][j];
			}
		}
	}
	cout << ans;
	return 0;
}