#include <bits/stdc++.h>
using namespace std;
const int mx = 2e3+5;
const int inf = 1e9+5;
int n, m;
int a[mx][mx];
int b[mx][mx];
int mn = inf, ma = 0;
int IOI, JOI;
bool check1(int x) {
int pre = m;
for (int i=1;i<=n;i++) {
int mn = m+1;
int ma = 0;
for (int j=1;j<=m;j++) {
if (abs(IOI-a[i][j]) > x) ma = max(ma, j);
if (abs(JOI-a[i][j]) > x) mn = min(mn, j);
if (abs(IOI-a[i][j]) > x and abs(JOI-a[i][j]) > x) return 0;
}
if (mn < ma or ma > pre) return 0;
pre = min(pre, mn-1);
}
return true;
}
bool check2(int x) {
int pre = m;
for (int i=1;i<=n;i++) {
int mn = m+1;
int ma = 0;
for (int j=1;j<=m;j++) {
if (abs(IOI-b[i][j]) > x) ma = max(ma, j);
if (abs(JOI-b[i][j]) > x) mn = min(mn, j);
if (abs(IOI-a[i][j]) > x and abs(JOI-a[i][j]) > x) return 0;
}
if (mn < ma or ma > pre) return 0;
pre = min(pre, mn-1);
}
return true;
}
signed main() {
cin >> n >> m;
for (int i=1;i<=n;i++) {
for (int j=1;j<=m;j++) {
cin >> a[i][j];
mn = min(mn, a[i][j]);
ma = max(ma, a[i][j]);
b[n-i+1][j] = a[i][j];
}
}
IOI = ma;
JOI = mn;
int l = 0, r = ma - mn;
while (l < r) {
int m = l + r >> 1;
if (check1(m) or check2(m)) {
r = m;
} else {
l = m+1;
}
}
int ans = l;
{
IOI = mn;
JOI = ma;
int l = 0, r = ma - mn;
while (l < r) {
int m = l + r >> 1;
if (check1(m) or check2(m)) {
r = m;
} else {
l = m+1;
}
}
ans = min(ans, l);
}
cout << ans << "\n";
}
