#include<bits/stdc++.h>
#pragma GCC optimize(2)
#pragma GCC optimize(3,"Ofast","inline")
#define int long long
inline int read(){
	int x=0,f=1;
	char ch=getchar();
	while(ch<'0'||ch>'9'){
		if(ch=='-') f=-1;
		ch=getchar();
	}
	while(ch>='0'&&ch<='9'){
		x=(x<<1)+(x<<3)+(ch^48);
		ch=getchar();
	}
	return x*f;
}
void write(int x){
	if(x<0){
		putchar('-');
		x=-x;
	}
	if(x>9){
		write(x/10);
	}
	putchar(x%10+'0');
}
using namespace std;
int g[1001][1001];
int sum[1001][1001];
int ma[1001],mi[1001];
signed main(){
	int a,b,n;
	a=read();
	b=read();
	n=read();
	for(int i=1;i<=a;i++){
		for(int j=1;j<=b;j++){
			g[i][j]=read();
		}
	}
	int ans=0x7fffffff;
	for(int i=1;i<=a-n+1;i++){
		for(int j=1;j<=b;j++){
			ma[j]=-0x7fffffff,mi[j]=0x7fffffff;
			bool flag=true;
			for(int k=i;k<=i+n-1;k++){
				ma[j]=max(ma[j],g[k][j]);
				mi[j]=min(mi[j],g[k][j]);
				
			}
			int maxn=-0x7fffffff,minn=0x7fffffff;
			if(j>=n){
				for(int l=j-n+1;l<=j;l++){
					maxn=max(maxn,ma[l]);
					minn=min(minn,mi[l]);
				}
				ans=min(ans,maxn-minn);
			}
		}
	}
	write(ans);
	return 0;
}