1 #include<bits/stdc++.h>
2 using namespace std;
3 typedef long long ll;
4 typedef double db;
5 #define INF 0x3f3f3f3f
6 #define _for(i,a,b) for(int i = (a);i < b;i ++)
7 #define _rep(i,a,b) for(int i = (a);i > b;i --)
8 inline ll read()
9 {
10 ll ans = 0;
11 char ch = getchar(), last = ' ';
12 while(!isdigit(ch)) last = ch, ch = getchar();
13 while(isdigit(ch)) ans = (ans << 1) + (ans << 3) + ch - '0', ch = getchar();
14 if(last == '-') ans = -ans;
15 return ans;
16 }
17 inline void write(ll x)
18 {
19 if(x < 0) x = -x, putchar('-');
20 if(x >= 10) write(x / 10);
21 putchar(x % 10 + '0');
22 }
23 int a,b,n;
24 int Log[1003];
25 int maxx[1003][1003][11];
26 int minn[1003][1003][11];
27 void searchLog()
28 {
29 Log[0] = -1;
30 _for(i,1,max(a,b)+1)
31 Log[i] = Log[i/2]+1;
32 }
33 int query(int x,int y)
34 {
35 int xl = x+n-1,yl = y+n-1;
36 int s = Log[n];
37 int MAX = max(maxx[x][y][s],max(maxx[xl-(1<<s)+1][yl-(1<<s)+1][s],
38 max(maxx[xl-(1<<s)+1][y][s],maxx[x][yl-(1<<s)+1][s])));
39
40 int MIN = min(minn[x][y][s],min(minn[xl-(1<<s)+1][yl-(1<<s)+1][s],
41 min(minn[xl-(1<<s)+1][y][s],minn[x][yl-(1<<s)+1][s])));
42 return MAX-MIN;
43 }
44 int main()
45 {
46 a = read(),b = read(), n = read();
47 searchLog();
48 _for(i,1,a+1)
49 _for(j,1,b+1)
50 minn[i][j][0] = maxx[i][j][0] = read();
51
52 _for(r,1,Log[n]+1)
53 for(int i = 1;i + (1<<r) - 1 <= a;i ++)
54 for(int j = 1;j + (1<<r) -1 <= b;j ++)
55 {
56 maxx[i][j][r] = max(maxx[i][j][r-1],max(maxx[i][j+(1<<r-1)][r-1],
57 max(maxx[i+(1<<r-1)][j][r-1],maxx[i+(1<<r-1)][j+(1<<r-1)][r-1])));
58
59 minn[i][j][r] = min(minn[i][j][r-1],min(minn[i][j+(1<<r-1)][r-1],
60 min(minn[i+(1<<r-1)][j][r-1],minn[i+(1<<r-1)][j+(1<<r-1)][r-1])));
61 }
62
63 int ans = INT_MAX;
64 _for(i,1,a-n+2)
65 _for(j,1,b-n+2)
66 ans = min(ans,query(i,j));
67 write(ans);
68 return 0;
69 }
