#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic warning "-Wunused-function"
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, m;
  cin >> n >> m;
  VI s(n), t(m);
  rep(i, n) cin >> s[i];
  rep(i, m) cin >> t[i];
  sort(all(s));
  sort(all(t));
  auto f = [&](int c) {
    int res = 0;
    int ptr = 0;
    for (int si : s) {
      while (ptr < m && t[ptr] < si - c) ptr++;
      if (ptr < m && t[ptr] <= si) res++, ptr++;
    }
    return res;
  };
  constexpr int INF = 1001001001;
  int mx = f(INF);
  int l = -1, r = INF;
  while (r - l > 1) {
    int c = (l + r) / 2;
    (f(c) == mx ? r : l) = c;
  }
  cout << r << '\n';
}