#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vector<int>;

#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
#define rep(i,a,b) for (int i = (a); i < (b); ++i)

mt19937 rng(random_device{}());

int main()
{
    cin.tie(0)->sync_with_stdio(0);

    int n;
    cin >> n;
    ll orr = 0;
    rep(i, 0, n) {
        ll a;
        cin >> a;
        orr |= a;
    }
    ll x = 1;
    while (x & orr) x <<= 1;
    cout << x << endl;

    return 0;
}