#include <bits/stdc++.h>
using namespace std;
int a,b,n;
long long mtx[1100][1100];
long long maxmtx[1100][1100],minmtx[1100][1100];
int _log;
long long ques(int x,int y)
{
	int _max=0,_min=0;
	_max=max(maxmtx[x][y],max(maxmtx[x+n-(1<<_log)][y+n-(1<<_log)],max(maxmtx[x+n-(1<<_log)][y],maxmtx[x][y+n-(1<<_log)])));
	_min=min(minmtx[x][y],min(minmtx[x+n-(1<<_log)][y+n-(1<<_log)],min(minmtx[x+n-(1<<_log)][y],minmtx[x][y+n-(1<<_log)])));
	return _max-_min;
}
int main()
{
	scanf("%d %d %d",&a,&b,&n);
	for (int i=0;i<a;i++)
	{
		for (int j=0;j<b;j++)
		{
			scanf("%lld",&mtx[i][j]);
			maxmtx[i][j]=minmtx[i][j]=mtx[i][j];
		}
	}
	for (_log=0;((1<<(_log+1))<=n);_log++);
	for (int k=0;k<_log;k++)
	{
		for (int i=0;i+(1<<k)<=a;i++)
		{
			for (int j=0;j+(1<<k)<=b;j++)
			{
				maxmtx[i][j]=max(maxmtx[i][j],max(maxmtx[i+(1<<k)][j+(1<<k)],max(maxmtx[i+(1<<k)][j],maxmtx[i][j+(1<<k)])));
				minmtx[i][j]=min(minmtx[i][j],min(minmtx[i+(1<<k)][j+(1<<k)],min(minmtx[i+(1<<k)][j],minmtx[i][j+(1<<k)])));
			}
		}
	}
	long long ans=10000000000;
	for (int i=0;i<=a-n;i++)
	{
		for (int j=0;j<=b-n;j++)
		{
			ans=min(ans,ques(i,j));
		}
	}
	printf("%lld\n",ans);
	return 0;
}