#include <bits/stdc++.h>
using namespace std;
int main(){
    int n;
    cin >> n;
    vector<long long int> A(n);
    for (int i = 0; i < n ;i++){
        cin >> A[i];
    }
    int cnt = 0;
    int idx = 0;
    bool fg = true;
    int sum = 0;
    while(fg || cnt){
        fg = false;
        for (int i = 0; i < n; i++){
            if (A[i] % 2 == 1) cnt++;
            A[i] /= 2;
            if (A[i]) fg = true;
        }
        if (cnt)
            sum += (1 << idx);
        idx++;
        cnt /= 2;
        
    }
    cout << sum << endl;
}