#include<iostream>

#include<cstdio>

#include<cstring>

using namespace std;

int const maxn=;

int a,b,n,m[maxn][maxn],hmn[maxn][maxn],mn,hmx[maxn][maxn],mx;

int w[maxn],qmn[maxn],qmx[maxn],headn,tailn,headx,tailx,ans;

int main()

{

    scanf("%d%d%d",&a,&b,&n);

    for(int i=,x;i<=a;i++)

    {

        headn=;tailn=;headx=;tailx=;//

        for(int j=;j<=b;j++)

        {

            scanf("%d",&w[j]);int x=w[j];

            if(j-qmn[headn]>=n)headn++;//位置而非个数

            if(j-qmx[headx]>=n)headx++;

            while(headn<=tailn&&x<=w[qmn[tailn]])tailn--;

            while(headx<=tailx&&x>=w[qmx[tailx]])tailx--;

            qmn[++tailn]=j;qmx[++tailx]=j;//

            hmn[i][j]=w[qmn[headn]];hmx[i][j]=w[qmx[headx]];

        }

    }

    ans=1e9;

    for(int j=;j<=b;j++)

    {

        headn=;tailn=;headx=;tailx=;

        for(int i=;i<=a;i++)

        {

            int x=hmn[i][j],y=hmx[i][j];

            if(i-qmn[headn]>=n)headn++;//

            if(i-qmx[headx]>=n)headx++;

            while(headn<=tailn&&x<=hmn[qmn[tailn]][j])tailn--;

            while(headx<=tailx&&y>=hmx[qmx[tailx]][j])tailx--;

            qmn[++tailn]=i;qmx[++tailx]=i;

            mn=hmn[qmn[headn]][j];mx=hmx[qmx[headx]][j];

            if(i<n||j<n)continue;//||

            ans=min(ans,mx-mn);

        }

    }

    printf("%d",ans);

    return ;

}