#include <bits/stdc++.h>
#define Aiko ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
#define pb push_back
using namespace std;
const int INF = 1e9;
signed main() {
int h, w, i, j;
cin >> h >> w;
vector<vector<int>> a(h, vector<int>(w));
int mx = 0, mn = INF;
for (i = 0; i < h; i++) {
for (j = 0; j < w; j++) {
cin >> a[i][j];
mn = min(mn, a[i][j]);
mx = max(mx, a[i][j]);
}
}
vector<vector<int>> color(h, vector<int>(w));
auto fun = [&](int t) {
for (i = 0; i < h; i++) {
for (j = 0; j < w; j++) {
if (abs(a[i][j] - mn) <= t) color[i][j] = 1;
}
}
for (i = 0; i < h; i++) {
for (j = 0; j < w; j++) {
if (color[i][j] != 1 && abs(a[i][j] - mx) <= t) color[i][j] = 2;
else if (abs(a[i][j] - mx) <= t) color[i][j] = 3;
}
}
vector<int> ans(h), ans1(h), ans2(w), ans3(w);
for (i = 0; i < h; i++) {
bool a2 = 0;
for (j = 0; j < w; j++) {
if (color[i][j] == 1) ans[i] = j;
if (color[i][j] == 2 && a2 == 0) {
a2 = 1;
ans1[i] = j;
}
}
}
for (i = 0; i < h; i++) {
bool a2 = 0;
for (j = 0; j < h; j++) {
if (color[i][j] == 1) ans[i] = j;
if (color[i][j] == 2 && a2 == 0) {
a2 = 1;
ans1[i] = j;
}
}
}
for (i = 0; i < w; i++) {
bool a2 = 0;
for (j = 0; j < h; j++) {
if (color[i][j] == 1) ans2[i] = j;
if (color[i][j] == 2 && a2 == 0) {
a2 = 1;
ans3[i] = j;
}
}
}
bool a1 = 0;
for (i = 0; i < h; i++) {
if (ans[i] > ans1[i]) a1 = 1;
}
for (i = 0; i < w; i++) {
if (ans2[i] > ans3[i]) a1 = 1;
}
if (a1 == 1) return false;
else return true;
};
int l = 0, r = 1e9 + 7;
while (r > l + 1) {
int m = (l + r) >> 1;
if (fun(m)) r = m;
else l = m;
}
if (fun(r)) cout << r;
else cout << l;
}
