#include <bits/stdc++.h>
using namespace std;
//types
#define ll long long
#define ld long double
#define pll pair<ll, ll>
#define pii pair<int, int>
#define fi first
#define se second
#define inf 0x3f3f3f3f
#define pb(a) push_back(a)
#define mp(a, b) make_pair(a, b)
//lowercase 31, all 53
//(P/Q) % M = (P % M) * (Q^(M-2) % M)
//-------------------------------------------------------
const ll mx = 1e5+5, mod = 1e9+7;
ll n, m;
vector<ll> a, b;
bool check(ll x)
{
ll i = n, j = m;
while (i >= 1)
{
if (j < 1) return false;
while (j >= 1)
{
if (abs(b[i] - a[j]) <= x)
{
j--;
break;
}
else
j--;
}
i--;
}
return true;
}
int main()
{
ios::sync_with_stdio(0);
cin.tie(0), cout.tie(0);
cin >> n >> m;
a.pb(-inf);
b.pb(-inf);
for (int i = 1; i <= n; i++) {
int tmp;
cin >> tmp;
a.pb(tmp);
}
for (int i = 1; i <= m; i++) {
int tmp;
cin >> tmp;
b.pb(tmp);
}
sort(a.begin()+1, a.end());
sort(b.begin()+1, b.end());
if (a.size() > b.size()) {
swap(a, b);
swap(n, m);
}
ll l = 0, r = 1e9, kq = 1e9;
while (l <= r)
{
ll mid = (l+r) / 2;
if (check(mid))
{
r = mid - 1;
kq = mid;
}
else
l = mid + 1;
}
cout << kq;
}
