#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); i++)
using ll = long long;
using vll = vector<ll>;
using vi = vector<int>;
using vvi = vector<vector<int>>;
using vvll = vector<vector<ll>>;
const ll inf = 1e16;
const ll md = 1000000007;

int main() {
  int n;
  cin >> n;
  vi a(n);
  rep(i,n) cin>>a[i];
  int s=0;
  rep(i,n) s|=a[i];
  cout<<s<<endl;
  return 0;
}