#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define st first
#define nd second
typedef long long ll;
typedef long double ld;
const ll I = 1000'000'000'000'000'000LL;
const int II = 2'000'000'000;
const ll M = 1000'000'007LL;
const int N = 2007;
int tab[N][N];
int t1[N][N], t2[N][N];
int m1[N][N], m2[N][N];
int dp[N][N];
void Calc(int n, int m)
{
for(int i = 1; i <= n; ++i)
for(int j = 1; j <= m; ++j)
m1[i][j] = max(t1[i][j], m1[i][j - 1]);
for(int i = 1; i <= n; ++i)
for(int j = m; j >= 1; --j)
m2[i][j] = max(t2[i][j], m2[i][j + 1]);
}
int LiczDP(int n, int m)
{
Calc(n, m);
for(int i = 1; i <= n; ++i)
{
dp[i][m + 1] = II;
for(int j = m; j >= 0; --j)
{
dp[i][j] = max(dp[i - 1][j], max(m1[i][j], m2[i][j + 1]));
dp[i][j] = min(dp[i][j], dp[i][j + 1]);
}
}
return dp[n][0];
}
void Solve()
{
int n, m, mi = II, ma = -1;
cin >> n >> m;
for(int i = 1; i <= n; ++i)
for(int j = 1; j <= m; ++j)
{
cin >> tab[i][j];
mi = min(mi, tab[i][j]);
ma = max(ma, tab[i][j]);
}
for(int i = 1; i <= n; ++i)
for(int j = 1; j <= m; ++j)
{
t1[i][j] = tab[i][j] - mi;
t2[i][j] = ma - tab[i][j];
}
int ans = II;
for(int r = 0; r < 2; ++r)
{
for(int l = 0; l < 2; ++l)
{
ans = min(ans, LiczDP(n, m));
for(int i = 1; i <= n; ++i)
for(int j = 1; j <= m; ++j)
swap(t1[i][j], t2[i][j]);
}
for(int i = 1; i <= n; ++i)
for(int j = 1; j <= m / 2; ++j)
{
swap(t1[i][j], t1[i][m - j + 1]);
swap(t2[i][j], t2[i][m - j + 1]);
}
}
cout << ans << "\n";
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
//int t; cin >> t;
//while(t--)
Solve();
return 0;
}
