/**
	Author: 丘成桐(囯内)
**/
#include<bits/stdc++.h>
#define int long long
using namespace std;
void ts(){cout<<"IAKIOI\n";}
int n,m,k;
int a[1005][1005];
int b[1005][1005];
int c[1005][1005];
int d[1005][1005];
int e[1005][1005];
void solve(){
	priority_queue<int,vector<int>,greater<int>> pq,del;
	for(int i=1;i<=n;i++){
		while(!pq.empty())pq.pop();
		while(!del.empty())del.pop();
		for(int j=1;j<=k;j++)pq.push(a[i][j]);
		d[i][1]=pq.top();
		for(int j=k+1;j<=m;j++){
			pq.push(a[i][j]);
			del.push(a[i][j-k]);
			while(!pq.empty()&&!del.empty()&&pq.top()==del.top())pq.pop(),del.pop();
			d[i][j-k+1]=pq.top();
		}
	}
	for(int i=1;i<=m-k+1;i++){
		while(!pq.empty())pq.pop();
		while(!del.empty())del.pop();
		for(int j=1;j<=k;j++)pq.push(d[j][i]);
		e[1][i]=pq.top();
		for(int j=k+1;j<=n;j++){
			pq.push(d[j][i]);
			del.push(d[j-k][i]);
			while(!pq.empty()&&!del.empty()&&pq.top()==del.top())pq.pop(),del.pop();
			e[j-k+1][i]=pq.top();
		}
	}
}
signed main(){
ios::sync_with_stdio(0),cin.tie(0);
	cin>>n>>m>>k;
	for(int i=1;i<=n;i++)for(int j=1;j<=m;j++)cin>>a[i][j];
	priority_queue<int> pq,del;
	for(int i=1;i<=n;i++){
		while(!pq.empty())pq.pop();
		while(!del.empty())del.pop();
		for(int j=1;j<=k;j++)pq.push(a[i][j]);
		b[i][1]=pq.top();
		for(int j=k+1;j<=m;j++){
			pq.push(a[i][j]);
			del.push(a[i][j-k]);
			while(!pq.empty()&&!del.empty()&&pq.top()==del.top())pq.pop(),del.pop();
			b[i][j-k+1]=pq.top();
		}
	}
	for(int i=1;i<=m-k+1;i++){
		while(!pq.empty())pq.pop();
		while(!del.empty())del.pop();
		for(int j=1;j<=k;j++)pq.push(b[j][i]);
		c[1][i]=pq.top();
		for(int j=k+1;j<=n;j++){
			pq.push(b[j][i]);
			del.push(b[j-k][i]);
			while(!pq.empty()&&!del.empty()&&pq.top()==del.top())pq.pop(),del.pop();
			c[j-k+1][i]=pq.top();
		}
	}
	solve();
	int res=(1ll<<60);
	for(int i=1;i<=n-k+1;i++){
		for(int j=1;j<=m-k+1;j++)res=min(res,c[i][j]-e[i][j]);
	}
	cout<<res<<"\n";
	return 0;
}