#include <bits/stdc++.h>
using namespace std;

#define LL int64_t

struct Node {
	int nVal;
	int nPosX, nPosY;
}n[1005][1005], max1[1005][1005], min1[1005][1005];

int a, b, k;
int max2[1005][1005];
int min2[1005][1005];
int nAns = 0xFFFFFFF;

void solve() {
	cin >> a >> b >> k;
	for(int i = 1; i <= a; ++i)
		for(int j = 1; j <= b; ++j) {
			cin >> n[i][j].nVal;
			n[i][j].nPosX = i, n[i][j].nPosY = j;
		}
	for(int i = 1; i <= a; ++i) {
		deque<Node> q1, q2;
		for(int j = 1; j <= b; ++j) {
			while(q1.size() && q1.back().nVal <= n[i][j].nVal) q1.pop_back();
			q1.push_back(n[i][j]);
			while(q1.size() && q1.front().nPosY <= j - k) q1.pop_front();
			if(j >= k) {
				max1[i][j - k + 1].nVal = q1.front().nVal;
				max1[i][j - k + 1].nPosX = i;
				max1[i][j - k + 1].nPosY = j - k + 1;
			}
			while(q2.size() && q2.back().nVal >= n[i][j].nVal) q2.pop_back();
			q2.push_back(n[i][j]);
			while(q2.size() && q2.front().nPosY <= j - k) q2.pop_front();
			if(j >= k) {
				min1[i][j - k + 1].nVal = q2.front().nVal;
				min1[i][j - k + 1].nPosX = i;
				min1[i][j - k + 1].nPosY = j - k + 1;
			}
		}
	}
	for(int j = 1; j <= b - k + 1; ++j) {
		deque<Node> q1, q2;
		for(int i = 1; i <= a; ++i) {
			while(q1.size() && q1.back().nVal <= max1[i][j].nVal) q1.pop_back();
			q1.push_back(max1[i][j]);
			while(q1.size() && q1.front().nPosX <= i - k) q1.pop_front();
			if(i >= k) max2[i - k + 1][j] = q1.front().nVal;
			while(q2.size() && q2.back().nVal >= min1[i][j].nVal) q2.pop_back();
			q2.push_back(min1[i][j]);
			while(q2.size() && q2.front().nPosX <= i - k) q2.pop_front();
			if(i >= k) min2[i - k + 1][j] = q2.front().nVal;
		}
	}
	for(int i = 1; i <= a - k + 1; ++i) 
		for(int j = 1; j <= b - k + 1; ++j) 
			if(nAns > max2[i][j] - min2[i][j])
				nAns = max2[i][j] - min2[i][j];
	cout << nAns << '\n';
}

int main() {
	int T = 1;
	/* cin >> T; */
	while(T--) solve();

	return 0;
}