#include <bits/stdc++.h>
using namespace std;
void setup()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
}
int n, m, a, mina = 1e9, maxa = -1e9, l, r, mid, res;
pair<int, int> pre[2002][2002], suf[2002][2002];
inline bool Check(int inp)
{
int upmax = m, upmin = m , downmax = m, downmin = m;
bool v1 = true, v2 = true, v3 = true, v4 = true;
for (int i = 1; i <= n; ++i)
{
while (0 < upmax && maxa - pre[i][upmax].first > inp)
{
upmax--;
}
while (0 < upmin && pre[i][upmin].second - mina > inp)
{
upmin--;
}
v1 &= (suf[i][upmax + 1].second - mina <= inp);
v2 &= (maxa - suf[i][upmin + 1].first <= inp);
}
for (int i = n; i >= 1; --i)
{
while (0 < downmax && maxa - pre[i][downmax].first > inp)
{
downmax--;
}
while (0 < downmin && pre[i][downmin].second - mina > inp)
{
downmin--;
}
v3 &= (suf[i][downmax + 1].second - mina <= inp);
v4 &= (maxa - suf[i][downmin + 1].first <= inp);
}
return v1 | v2 | v3 | v4;
}
int main()
{
setup();
cin >> n >> m;
for (int i = 1; i <= n; ++i)
{
pre[i][0] = pre[i][m + 1] = suf[i][0] = suf[i][m + 1] = {1e9, -1e9};
for (int j = 1; j <= m; ++j)
{
cin >> a;
mina = min(mina, a);
maxa = max(maxa, a);
pre[i][j] = suf[i][j] = {a, a};
pre[i][j].first = min(pre[i][j].first, pre[i][j - 1].first);
pre[i][j].second = max(pre[i][j].second, pre[i][j - 1].second);
}
for (int j = m; j >= 1; --j)
{
suf[i][j].first = min(suf[i][j].first, suf[i][j + 1].first);
suf[i][j].second = max(suf[i][j].second, suf[i][j + 1].second);
}
}
l = 0;
r = 1e9;
while (l <= r)
{
mid = (l + r) >> 1;
if (Check(mid))
{
res = mid;
r = mid - 1;
}
else
{
l = mid + 1;
}
}
cout << res;
return 0;
}
