#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;
typedef tree<int, null_type, less<int>, rb_tree_tag,tree_order_statistics_node_update> ordered_set;

#define scan(x) do{while((x=getchar())<'0'); for(x-='0'; '0'<=(_=getchar()); x=(x<<3)+(x<<1)+_-'0');}while(0)
char _;
#define complete_unique(a) a.erase(unique(a.begin(),a.end()),a.end())
#define all(a) a.begin(),a.end()
#define println printf("\n");
#define readln(x) getline(cin,x);
#define pb push_back
#define endl "\n"
#define INT_INF 0x3f3f3f3f
#define LL_INF 0x3f3f3f3f3f3f3f3f
#define MOD 1000000007
#define MOD2 1190492669
#define SEED 131
#define mp make_pair
#define fastio cin.tie(0); cin.sync_with_stdio(0);

#define MAXN 1005

typedef unsigned long long ull;
typedef long long ll;
typedef long double ld;
typedef unordered_map<int,int> umii;
typedef pair<int,int> pii;
typedef pair<double,double> pdd;
typedef pair<ll,ll> pll;
typedef pair<int,pii> triple;
typedef int8_t byte;

mt19937 g1(time(0));

int randint(int a, int b){return uniform_int_distribution<int>(a, b)(g1);}
ll randlong(ll a,ll b){return uniform_int_distribution<long long>(a, b)(g1);}

ll gcd(ll a, ll b){return b == 0 ? a : gcd(b, a % b);}
ll lcm(ll a, ll b){return a*b/gcd(a,b);}
ll fpow(ll  b, ll exp, ll mod){if(exp == 0) return 1;ll t = fpow(b,exp/2,mod);if(exp&1) return t*t%mod*b%mod;return t*t%mod;}
ll divmod(ll i, ll j, ll mod){i%=mod,j%=mod;return i*fpow(j,mod-2,mod)%mod;}

struct node{
    int l,r,mn,mx;
};

int num_rows,num_cols,N,arr[MAXN][MAXN],mx[MAXN][MAXN],mn[MAXN][MAXN],res=INT_MAX;
node seg[4*MAXN];

inline void push_up(int rt){
    seg[rt].mn = min(seg[rt<<1].mn,seg[rt<<1|1].mn);
    seg[rt].mx = max(seg[rt<<1].mx,seg[rt<<1|1].mx);
}

void build(int l, int r, int rt, int col){
    seg[rt].l = l, seg[rt].r = r, seg[rt].mn = INT_MAX, seg[rt].mn = INT_MIN;
    if(l == r){
        seg[rt].mn = mn[l][col];
        seg[rt].mx = mx[l][col];
        return;
    }
    int mid = (l+r)/2;
    build(l,mid,rt<<1,col);
    build(mid+1,r,rt<<1|1,col);
    push_up(rt);
}

pii query(int l, int r, int rt){
    if(seg[rt].l == l && seg[rt].r == r) return mp(seg[rt].mn,seg[rt].mx);
    int mid = (seg[rt].l+seg[rt].r)/2;
    if(r <= mid) return query(l,r,rt<<1);
    else if(l > mid) return query(l,r,rt<<1|1);
    else{
        pii f = query(l,mid,rt<<1), s = query(mid+1,r,rt<<1|1);
        return mp(min(f.first,s.first),max(f.second,s.second));
    }
}

int main(){
    scanf("%d %d %d",&num_rows,&num_cols,&N);
    for(int i=1; i<=num_rows; i++)
        for(int k=1; k<=num_cols; k++)
            scanf(" %d",&arr[i][k]);
    for(int i=1; i<=num_rows; i++){
        deque<pii> mix,max;
        for(int k=1; k<=num_cols; k++){
            while(mix.size() && mix.front().second+N <= k) mix.pop_front();
            while(max.size() && max.front().second+N <= k) max.pop_front();

            while(mix.size() && mix.back().first >= arr[i][k]) mix.pop_back();
            while(max.size() && max.back().first <= arr[i][k]) max.pop_back();
            mix.pb(mp(arr[i][k],k));
            max.pb(mp(arr[i][k],k));
            mx[i][k] = max.front().first;
            mn[i][k] = mix.front().first;
        }
    }
    for(int i=N; i<=num_cols; i++){
        build(1,num_rows,1,i);
        for(int k=N; k<=num_rows; k++){
            pii q = query(k-N+1,k,1);
            res = min(res,q.second-q.first);
        }
    }
    printf("%d\n",res);
}