//#define _CRT_SECURE_NO_WARNINGS

#include <stdlib.h>
#include <string>
#include <vector>
#include <cstdio>
#include<iterator>

using namespace std;

int compare(const void * a, const void * b)
{
	return (*(int*)a - *(int*)b);
}

int main()
{
	int n = 0;

	freopen("combine.in", "r", stdin);
	freopen("combine.out", "w", stdout);

	scanf("%d", &n);
	vector<int> a(n);

	for (int i = 0; i < n; i++)
	{//
		scanf("%d", &a[i]);
	}

	qsort(&a[0], n, sizeof(int), compare);

	vector<int> b;
	bool isChanged = true;

	while (isChanged)
	{
		isChanged = false;
		int i = 0;
		for (vector<int>::iterator it = a.begin(); it != a.end() && i < a.size() - 1; ++it, i++)
		{
			if (a[i] == a[i + 1])
			{
				a[i] = a[i] + a[i + 1];
				a.erase(it + 1);
				isChanged = true;
			}
		}
	}

	printf("%d", a[0]);
}