rt

#include<bits/stdc++.h>
using namespace std;
int a,b,n,logg;
int ep[12],stmx[1024][1024][12],stmn[1024][1024][12],shu[1024][1024],ans;
int dod(int stx,int sty){
    int maxx=(max(stmx[stx][sty][logg],max(stmx[stx+n-ep[logg]+1][sty+n-ep[logg]+1][logg],max(stmx[stx][sty+n-ep[logg]+1][logg],stmx[stx+n-ep[logg]+1][sty][logg]))));
    int minn=(min(stmn[stx][sty][logg],min(stmn[stx+n-ep[logg]+1][sty+n-ep[logg]+1][logg],min(stmn[stx][sty+n-ep[logg]+1][logg],stmn[stx+n-ep[logg]+1][sty][logg]))));
    //cout<<maxx<<" "<<minn<<" ";
    return maxx-minn;
}
int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    memset(stmn,0x3f,sizeof(stmn));
    cin>>a>>b>>n;
    logg=log2(n);
    ep[0]=1;
    for(int i=1;i<=10;i++){
        ep[i]=ep[i-1]*2;
    }
    for(int i=1;i<=a;i++){
        for(int j=1;j<=b;j++){
            cin>>shu[i][j];
            stmx[i][j][0]=shu[i][j];
            stmn[i][j][0]=shu[i][j];
        }
    }
    for(int i=1;i<=logg;i++){
        for(int j=1;j<=a-ep[i-1]+1;j++){
            for(int k=1;k<=b-ep[i-1]+1;k++){
                stmx[j][k][i]=max(stmx[j][k][i-1],max(stmx[j+ep[i-1]][k][i-1],max(stmx[j][k+ep[i-1]][i-1],stmx[j+ep[i-1]][k+ep[i-1]][i-1])));
                stmn[j][k][i]=min(stmn[j][k][i-1],min(stmn[j+ep[i-1]][k][i-1],min(stmn[j][k+ep[i-1]][i-1],stmn[j+ep[i-1]][k+ep[i-1]][i-1])));
            }
        }
    }
    ans=0x3f3f3f3f;
    for(int j=1;j<=a-n+1;j++){
        for(int k=1;k<=b-n+1;k++){
            ans=min(ans,dod(j,k));
            //cout<<dod(j,k)<<" ";
        }
        //cout<<'\n';
    }
    cout<<ans;
}