#include<bits/stdc++.h>
using namespace std;
inline int read()
{
    register int x=0,f=1;
    char c=getchar();
    while(c<'0'||c>'9')
    {
        if(c=='-') f=-1;
        c=getchar();
    }
    while(c>='0'&&c<='9')
    {
        x=(x<<3)+(x<<1)+(c^48); 
        c=getchar();
    }
    return x*f;
}
const int N = 1005;
int a, b, n;
int w[N][N];
int fa[N][N], fi[N][N];
int ga[N][N], gi[N][N];
int minn[10005], h1 = 0, t1 = 0;
int maxn[10005], h2 = 0, t2 = 0;
int main() 
{
	a=read(),b=read(),n=read();
	for (int i = 1; i <= a; i++)
			for (int j = 1; j <= b; j++)
				w[i][j]=read();
	for (int i = 1; i <= a; i++) 
	{
		memset(minn, 0, sizeof(minn));
		h1=h2=1;
		t1=t2=0;
		memset(maxn, 0, sizeof(maxn));
		for (int j = 1; j <= b; j++) 
		{
			while (minn[h1] < j - n + 1 && h1 <= t1) h1++;
			while (maxn[h2] < j - n + 1 && h2 <= t2) h2++;
			while (w[i][minn[t1]] >= w[i][j] && h1 <= t1) t1--;
			while (w[i][maxn[t2]] <= w[i][j] && h2 <= t2) t2--;
			minn[++t1] = j;
			maxn[++t2] = j;
			fi[i][j] = w[i][minn[h1]];
			fa[i][j] = w[i][maxn[h2]];
		}
	}
	for (int i = 1; i <= b; i++) 
	{
		memset(minn, 0, sizeof(minn));
		h1=h2=1;
		t1=t2=1;
		memset(maxn, 0, sizeof(maxn));
		for (int j = 1; j <= a; j++) 
		{
			while (minn[h1] < j - n + 1 && h1 <= t1) h1++;
			while (maxn[h2] < j - n + 1 && h2 <= t2) h2++;
			while (fi[minn[t1]][i] >= fi[j][i] && h1 <= t1) t1--;
			while (fa[maxn[t2]][i] <= fa[j][i] && h2 <= t2) t2--;
			minn[++t1] = j;
			maxn[++t2] = j;
			gi[j][i] = fi[minn[h1]][i];
			ga[j][i] = fa[maxn[h2]][i];
		}
	}
	int ans = 0x3f3f3f3f;
	for (int i = n; i <= a; i++) 
		for (int j = n; j <= b; j++) 
			ans =min(ans, ga[i][j] - gi[i][j]);
	cout<<ans;
       return 0;
}