#include<cstdio>

#include<iostream>

#include<cstring>

#include<algorithm>

#include<vector>

using namespace std;

const int N=1e3+;

inline int read(){

    int X=,w=;char ch=;

    while(ch<''||ch>''){w|=ch=='-';ch=getchar();}

    while(ch>=''&&ch<='')X=(X<<)+(X<<)+(ch^),ch=getchar();

    return w?-X:X;

}

int a,b,n,g[N][N],t[N][N];

int re[][N][N],q[N][];

void solve(int k){

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

    int l=,r=;

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

        while(l<r&&j-q[l][]>=n)l++;

        if(!k)while(l<r&&t[i][j]>=q[r-][])r--;

        else while(l<r&&t[i][j]<=q[r-][])r--;

        q[r][]=t[i][j];q[r++][]=j;

        g[i][j]=q[l][];

    }

    }

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

    int l=,r=;

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

        while(l<r&&i-q[l][]>=n)l++;

        if(!k)while(l<r&&g[i][j]>=q[r-][])r--;

        else while(l<r&&g[i][j]<=q[r-][])r--;

        q[r][]=g[i][j];q[r++][]=i;

        re[k][i][j]=q[l][];

    }

    }

}

int main(){

    a=read(),b=read(),n=read();

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

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

        t[i][j]=read();

    }

    }

    solve();solve();

    int ans=1e9;

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

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

        ans=min(ans,re[][i][j]-re[][i][j]);

    }

    }

    printf("%d\n",ans);

    return ;

}