#include <iostream>
#include "vector"


std::vector<int> bit_repr(size_t num){
    std::vector<int> ret;
    while(num != 0){
        ret.push_back(num % 2);
        num /= 2;
    }
    return ret;
}

size_t get_num_from_bit_repr(std::vector<int> repr){
    size_t num = 0;
    size_t mul = 1;
    for (size_t i = 0; i < repr.size(); ++i){
        if(repr[i] == 1){
            num += mul;
        }
        mul = mul * 2;
    }
    return num;
}


int main() {
    size_t n;
    std::cin >> n;
    std::vector<size_t> nums;
    std::vector<int> res;

    for(size_t i = 0; i < n; ++i){
        size_t x;
        std::cin >> x;
        nums.push_back(x);
    }

    for(size_t numIdx = 0; numIdx < n; ++numIdx){
        size_t num = nums[numIdx];
        auto bits = bit_repr(num);
        ssize_t biggest_set = -1;

        for(size_t i = 0; i < bits.size(); ++i){
            if(i >= res.size()){
                res.push_back(0);
            }

            if(bits[i] == 0){
                continue;
            }

            if (biggest_set > (ssize_t)i) {
                continue;
            }
            //bit is 1
            //iterate until 0 is found => change it to 1
            size_t j = i;
            while(res[j]){
                ++j;
                if(j >= res.size()){
                    res.push_back(0);
                }
            }
            biggest_set = j;
            res[j] = 1;
        }
    }
    std::cout << get_num_from_bit_repr(res);

    return 0;
}