// mokre tricko


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

#define LSOne(S) ((S) & -(S))

int main() {

    int n;
    scanf("%d", &n);

    vector<long long> nums(n);

    vector<int> occ(70, 0); 

    long long summ = 0;

    for (int i = 0; i < n; i++) {
        scanf("%ld", &nums[i]);

        summ += nums[i];

        long long mm = nums[i];
        while (mm != 0) {
            long long r = LSOne(mm);
            int c = __builtin_ctz(r);
            occ[c]++;
            mm -= r;
        }
    }
    // long long mm = summ;
    // while (mm != 0) {
    //     long long r = LSOne(mm);
    //     int c = __builtin_ctz(r);
    //     occ[c]++;
    //     mm -= r;
    // }

    for (int i = 0; i < occ.size() - 1; ++i) {
        occ[i+1] += occ[i] / 2;
    }

    long long ans = 0;

    for (int i = 0; i < occ.size() - 1; ++i) if (occ[i] > 0) {
        ans |= 1ll << i;
    }

    // long long ans = 0;
    // long long subsetsum = 0;

    // for (int i = 0; i < n; ++i) {
    //     subsetsum += nums[i];
    //     ans = ans | subsetsum;
    // }

    printf("%ld\n", ans);



    return 0;
}