import java.util.Scanner;
import java.math.*;

public class Shopping {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int numbers = sc.nextInt();
        int[] bitCounters = new int[80];
        for (int i = 0; i < numbers; i++) {
            int value = sc.nextInt();
            for (int j = 0; value > 0; j++) {
                if (value % 2 == 1) {
                    bitCounters[j]++;
                }
                value /= 2;
            }
        }
        long answer = 0;
        long multiplier = 1;
        for (int i = 0; i < bitCounters.length - 1; i++) {
            if (bitCounters[i] > 0) {
                answer += multiplier;
            }
            bitCounters[i + 1] += bitCounters[i] / 2;
            multiplier *= 2;
        }
        System.out.println(answer);
    }
}