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

int A, B, N, t, ans = 0x3f3f3f3f;
vector<int> tmp0[1005], tmp1[1005], tmp2[1005];
vector<int> maxn[1005], minn[1005];

void putout(vector<int> a, string tmp = " "){
	for (auto && i : a){
		cout << i << tmp;
	}
	cout << "\n";
}

vector<int> calcMAX(vector<int> a){
	int l = 0;
	vector<int> q, res;
	for (int i = 0; i < (int)a.size(); i ++){
		while (l < (int)q.size() && i - q[l] + 1 > N) l ++;
		while (l < (int)q.size() && a[q.back()] < a[i]) q.pop_back();
		q.push_back(i);
		if (i >= N - 1) res.push_back(a[q[l]]);
	}
	return res;
}

vector<int> calcMIN(vector<int> a){
	int l = 0;
	vector<int> q, res;
	for (int i = 0; i < (int)a.size(); i ++){
		while (l < (int)q.size() && i - q[l] + 1 > N) l ++;
		while (l < (int)q.size() && a[q.back()] > a[i]) q.pop_back();
		q.push_back(i);
		if (i >= N - 1) res.push_back(a[q[l]]);
	}
	return res;
}

int main(){
#ifndef ONLINE_JUDGE
	freopen("../data.in", "r", stdin);
	freopen("../data.out", "w", stdout);
#endif

	scanf("%d %d %d", &A, &B, &N);
	for (int i = 0; i < A; i ++){
		for (int j = 0; j < B; j ++){
			scanf("%d", &t);
			tmp0[i].push_back(t);
		}
	}
	for (int i = 0; i < A; i ++){
		vector<int> tmp = calcMAX(tmp0[i]);
		for (int j = 0; j < B - N + 1; j ++){
			tmp1[j].push_back(tmp[j]);
		}
		tmp = calcMIN(tmp0[i]);
		for (int j = 0; j < B - N + 1; j ++){
			tmp2[j].push_back(tmp[j]);
		}
	}
	for (int i = 0; i < B - N + 1; i ++){
		vector<int> tmp = calcMAX(tmp1[i]);
		for (int j = 0; j < A - N + 1; j ++){
			maxn[j].push_back(tmp[j]);
		}
		tmp = calcMIN(tmp2[i]);
		for (int j = 0; j < A - N + 1; j ++){
			minn[j].push_back(tmp[j]);
		}
	}
	for (int i = 0; i < A - N + 1; i ++){
		for (int j = 0; j < B - N + 1; j ++){
			// printf("%d::%d ", maxn[i][j], minn[i][j]);
			ans = min(ans, maxn[i][j] - minn[i][j]);
		}
		// printf("\n");
	}
	printf("%d\n", ans);

	return 0;
}