#include <bits/stdc++.h>

//-----------Above is the header file-----------//

#define FOR(i,a,n) for(int i = (a) ; i <= (n) ; i++)
#define REF(i,n,a) for(int i = (n) ; i >= (a) ; i--)

using namespace std;

typedef long long ll;

const int N = 1e+3 + 7;
const int MOD = 1e+9 + 7;
const int INF = 0x3f3f3f3f;
const int _INF = -0x3f3f3f3f;

int a,b,n,ans = INF;
int mp[N][N];
int q1[N], h1 = 0, t1 = 0;
int q2[N], h2 = 0, t2 = 0;
int colmax[N][N], colmin[N][N], sqmax[N][N], sqmin[N][N];

void init(){
    memset(q1, 0, sizeof q1);
    memset(q2, 0 ,sizeof q2);
    h1 = t1 = h2 = t2 = 0;
    return;
}
    
int main(){

    cin.sync_with_stdio(false);
    cout.sync_with_stdio(false);

    scanf("%d %d %d",&a,&b,&n);
    FOR(i,1,a)
        FOR(j,1,b)
            scanf("%d",&mp[i][j]);
    FOR(i,1,a){
        init();
        FOR(j,1,b){
            while(t1 > h1 && mp[i][q1[t1 - 1]] >= mp[i][j])t1--;
            q1[t1++] = j;
            while(t1 > h1 && q1[h1] < j - n + 1)h1++;
            while(t2 > h2 && mp[i][q2[t2 - 1]] <= mp[i][j])t2--;
            q2[t2++] = j;
            while(t2 > h2 && q2[h2] < j - n + 1)h2++;
            if(j >= n){
                colmax[i][j - n + 1] = mp[i][q2[h2]];
                colmin[i][j - n + 1] = mp[i][q1[h1]];
            } 
        }
    }
    FOR(j,1,b - n + 1){
        init();
        FOR(i,1,a){
            while(t1 > h1 && colmin[q1[t1 - 1]][j] >= colmin[i][j])t1--;
            q1[t1++] = i;
            while(t1 > h1 && q1[h1] < i - n + 1)h1++;
            while(t2 > h2 && colmax[q2[t2 - 1]][j] <= colmax[i][j])t2--;
            q2[t2++] = i;
            while(t2 > h2 && q2[h2] < i - n + 1)h2++;
            if(i >= n){
                sqmax[i - n + 1][j] = colmax[q2[h2]][j];
                sqmin[i - n + 1][j] = colmin[q1[h1]][j];
            }
        }
    }
    FOR(i,1,a - n + 1)
        FOR(j,1,b - n + 1){
            ans = min(ans, sqmax[i][j] - sqmin[i][j]);
        }
    printf("%d",ans);
    return 0;
}