#include <bits/stdc++.h>
using namespace std;
int n,m,k,q[1005],q1[1005],a[2005][2005],head=1,tail=1,ans=0x3f3f3f3f,head1=1,tail1=1;
int min_r[1005][1005],min_c[1005][1005],max_r[1005][1005],max_c[1005][1005];
signed main() {
	cin>>n>>m>>k;
	for(int i=1; i<=n; i++) {
		for(int j=1; j<=m; j++) {
			scanf("%d",&a[i][j]);
		}
	}
	for(int i=1; i<=n-k+1; i++) {
		for(int j=1; j<=m-k+1; j++) {
			while(head<=tail&&a[i][q[tail]]>a[i][j]) {
				tail--;
			}
			q[++tail]=j;
			while(j-q[head]+1>k) {
				head++;
			}
			if(j>=k) {
				min_r[i][j]=a[i][q[head]];
			}
		}
	}
	memset(q,0,sizeof(q));
	head=tail=1;
	for(int i=1; i<=n-k+1; i++) {
		for(int j=1; j<=m-k+1; j++) {
			while(head<=tail&&a[i][q[tail]]<a[i][j]) {
				tail--;
			}
			q[++tail]=j;
			while(j-q[head]+1>k) {
				head++;
			}
			if(j>=k) {
				max_r[i][j]=a[i][q[head]];
			}
		}
	}
	memset(q,0,sizeof(q));
	head=tail=1;
	for(int i=1; i<=n-k+1; i++) {
		for(int j=1; j<=m-k+1; j++) {
			while(head<=tail&&max_r[i][q[tail]]<max_r[i][j]) {
				tail--;
			}
			q[++tail]=j;
			while(j-q[head]+1>k) {
				head++;
			}
			if(j>=k) {
				max_c[i][j]=max_r[i][q[head]];
			}
			while(head1<=tail1&&min_r[i][q1[tail]]<min_r[i][j]) {
				tail1--;
			}
			q1[++tail1]=j;
			while(j-q1[head1]+1>k) {
				head1++;
			}
			if(j>=k) {
				min_c[i][j]=min_r[i][q1[head1]];
			}
		}
	}
	
	for(int i=1;i<=n-k+1;i++){
		for(int j=1;j<=m-k+1;j++){
			ans=min(ans,max_c[i][j]-min_c[i][j]);
		}
	}
	cout<<ans;
}