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#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main() {
	ios_base::sync_with_stdio(0);
	int amount, number, size = 0;
	vector<int> numbers;
	cin >> amount;

	size = (1 + amount) * amount / 2;
	numbers.reserve(15);
	for (int i = 0; i < size; i++){
		cin >> number;
		numbers.push_back(number);
	}
	sort(numbers.begin(), numbers.end());
	number = 0;
	for (int i = 0; i<amount; i++)
		number += numbers[i];
	cout << number;
}