#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define int ll
#define pii pair<int, int>
#define ff first
#define ss second
int a[2011][2011], b[2010][2010];
int mn, mx;
int n, m;
bool check(int x){
for(int i=1; i<=n; i++){
for(int j=1; j<=m; j++){
int ok2=(mx - a[i][j] <= x), ok1=(a[i][j] - mn <= x);
if(!ok1 and !ok2) return 0;
if(ok1 and ok2){
b[i][j] = 0;
}
else if(ok1) b[i][j] = 1;
else if(ok2) b[i][j] = 2;
}
}
//cout<<x<<'\n';
//for(int i=1; i<=n; i++){
// for(int j=1; j<=m; j++){
// cout<<b[i][j];
// }
// cout<<'\n';
//}
int ls = 0;
for(int j=m; j>=1; j--){
for(int i=ls+1; i<=n; i++){
if(b[i][j] == 1){
ls = max(ls, i);
}
}
for(int i=1; i<=ls; i++){
if(b[i][j] == 2){
//cout<<a[i][j]<<'\n';
return 0 ;
}
}
}
return 1;
}
int solve(int N, int M){
n = N;
m = M;
int l=0, r=2e9 + 1;
while(l + 1 < r){
int mid=(l+r)/2;
if(check(mid)) r = mid;
else l = mid;
}
return r;
}
void rotate(){
for(int i=1; i<=n; i++){
for(int j=1; j<=m; j++){
b[m - j + 1][i] = a[i][j];
}
}
swap(n, m);
for(int i=1; i<=n; i++){
for(int j=1; j<=m; j++){
a[i][j] = b[i][j];
}
}
//for(int i=1; i<=n; i++){
// for(int j=1; j<=m; j++){
// cout<<a[i][j]<<' ';
// }
// cout<<'\n';
//}
}
void solve(){
cin>>n>>m;
mn = 1e9;
mx = 0;
for(int i=1; i<=n; i++){
for(int j=1; j<=m; j++){
cin>>a[i][j];
mn = min(mn, a[i][j]);
mx = max(mx, a[i][j]);
}
}
int ans = solve(n, m);
rotate();
ans = min(ans, solve(n, m));
rotate();
ans = min(ans, solve(n, m));
rotate();
ans = min(ans, solve(n, m));
cout<<ans<<'\n';
}
signed main(){
solve();
}
