#include<bits/stdc++.h>
#define int long long
using namespace std;
namespace IO{
	template<typename T> inline void read(T &x){
		bool f=1;x=0;char ch=getchar();
		while(ch<'0'||ch>'9'){if(ch=='-')f=0;ch=getchar();}
		while(ch>='0'&&ch<='9')x=(x<<1)+(x<<3)+(ch&15),ch=getchar();
		x=f?x:-x;
	}
	template<typename T> inline void write(T x){
		if(x<0) putchar('-'),x=-x;
	   	if(x>9) write(x/10);
	   	putchar(('0'+x%10));
	}
	template <typename T,typename ...Args> inline void read(T &x,Args &...args){read(x);read(args...);}
	template<typename T> inline void write(T x,char c){write(x),putchar(c);}
}
using namespace IO;
int a,b,n,logn,m[1005][1005],ans=INT_MAX;
int maxv[1005][1005],minv[1005][1005];
int query(int x, int y){
	int maxn=0,minn=0;
	maxn=max(maxv[x][y],max(maxv[x+n-(1<<logn)][y+n-(1<<logn)],max(maxv[x+n-(1<<logn)][y],maxv[x][y+n-(1<<logn)])));
	minn=min(minv[x][y],min(minv[x+n-(1<<logn)][y+n-(1<<logn)],min(minv[x+n-(1<<logn)][y],minv[x][y+n-(1<<logn)])));
	return maxn-minn;
}
signed main(){
	read(a,b,n);
	for(int i=0;i<a;++i)
		for(int j=0;j<b;++j){
			read(m[i][j]);
			maxv[i][j]=minv[i][j]=m[i][j];
		}
	logn=log2(n);
	for(int k=0;k<logn;++k)
		for(int i=0;i+(1<<k)<a;++i)
			for(int j=0;j+(1<<k)<b;++j){
				maxv[i][j]=max(maxv[i][j],max(maxv[i+(1<<k)][j+(1<<k)],max(maxv[i+(1<<k)][j],maxv[i][j+(1<<k)])));
				minv[i][j]=min(minv[i][j],min(minv[i+(1<<k)][j+(1<<k)],min(minv[i+(1<<k)][j],minv[i][j+(1<<k)])));
			}
	for(int i=0;i<=a-n;++i)
		for(int j=0;j<=b-n;++j)
			ans=min(ans,query(i,j));
	write(ans);
	return 0;
}