#include<bits/stdc++.h>
using namespace std;
#define re register
const int N = 1e3+9;
int A,B,n;
int a[N][N];
int q1[N*N],q2[N*N],l1,r1,l2,r2;
int mx[N][N],mi[N][N];

int main()
{
	scanf("%d%d%d",&A,&B,&n);
	for(re int i = 1;i <= A;i++)
		for(re int j = 1;j <= B;j++)
			scanf("%d",&a[i][j]);
	for(re int i = 1;i <= A;i++)
	{
		l1 = l2 = 1;r1 = r2 = 0;
		memset(q1,0,sizeof q1);
		memset(q2,0,sizeof q2);
		for(re int j = 1;j <= B;j++)
		{
			while(r1 >= l1 && q1[l1] < j-n+1)l1++;
			while(r1 >= l1 && a[i][q1[r1]] <= a[i][j])r1--;
			q1[++r1] = j;
			mx[i][j] = a[i][q1[l1]];
			
			while(r2 >= l2 && q2[l2] < j-n+1)l2++;
			while(r2 >= l2 && a[i][q2[r2]] >= a[i][j])r2--;
			q2[++r2] = j;
			mi[i][j] = a[i][q2[l2]];
			
		}
		
	}
	
//	for(int i = 1;i <= B;i++)
//	{
//		l1 = l2 = 1;r1 = r2 = 0;
//		memset(q1,0,sizeof q1);
//		memset(q2,0,sizeof q2);
//		for(int j = 1;j <= A;j++)
//		{
//			while(r1 >= l1 && q1[l1] < j-n+1)l1++;
//			while(r1 >= l1 && a[q1[r1]][i] <= a[j][i])r1--;
//			q1[++r1] = j;
//			mx[i][j][0] = a[q1[l1]][i];
//			
//			while(r2 >= l2 && q2[l2] < j-n+1)l2++;
//			while(r2 >= l2 && a[q2[r2]][i] >= a[j][i])r2--;
//			q2[++r2] = j;
//			mi[i][j][0] = a[q2[l2]][i];
//			
//		}
//		
//	}
	int ans = 1e9;
	for(re int i = n;i <= A;i++)
		for(re int j = n;j <= B;j++)
		{
			int mxx = -1,mii = 1e9;
			
			for(re int k = i-n+1;k <= i;k++)
				mxx = max(mxx,mx[k][j]),
				mii = min(mii,mi[k][j]);
			ans = min(ans,mxx-mii);
		}
	printf("%d",ans);
	return 0;
}