#include <bits/stdc++.h>
using namespace std;

#define int long long
const int maxn = 2e5 + 10;
int a[maxn], n;

signed main()
{
    ios_base::sync_with_stdio(0); cin.tie(0);
    if (fopen("input.in", "r")) {
        freopen("input.in", "r", stdin);
        freopen("output.out", "w", stdout);
    }
    int mx = 0, mn = LLONG_MAX, f = 0;
    cin>>n;
    for (int i=1; i<=n; i++) cin>>a[i], mx |= a[i], mn &= a[i], f |= (a[i] == 0);
    if (n == 1) return cout<<0, 0;
    int range = mx - mn + 1 + f;
    //ans = range - 1l<<(basis.size())
    int bmx = log2(mx), bmn = mn > 0 ? log2(mn) : 0, cnt = 0;
    for (int i=bmn; i<=bmx; i++)
    {
        int cur = LLONG_MAX;
        for (int j=1; j<=n; j++) if (a[j] >> i & 1) cur &= a[j];
        if (cur != (1ll<<i)) cnt++;
    }
    cout<<range-(1ll<<cnt);
}