#include <algorithm>
#include <sstream>
#include <iostream>
#include <vector>
#include <string>
//#include <gtest/gtest.h>

using std::vector;
using std::string;

bool compare_leading_digits(string s1, string s2) {
	return stoi(s1 + s2) > stoi(s2 + s1);
}

static string largest_number(vector<string> a) {
	string result = "";
	string maxDigit = "0";
	int indexHolder = 0;
	while (a.size() > 0){
		for (int i = 0; i< a.size(); i++) {
			if (compare_leading_digits(a[i], maxDigit)) {
				maxDigit = a[i];
				indexHolder = i;
			}
		}
		result = result + maxDigit;
		maxDigit = "0";
		a.erase(a.begin()+indexHolder);
	}
	return result;
}

//TEST(CompareLeadingDigits, CompareTest1) {
//	ASSERT_TRUE(compare_leading_digits("2", "21"));
//}
//
//TEST(CompareLeadingDigits, CompareTest2) {
//	ASSERT_FALSE(compare_leading_digits("20", "21"));
//}
//
//TEST(CompareLeadingDigits, CompareTest3) {
//	ASSERT_FALSE(compare_leading_digits("321", "322"));
//}
//
//TEST(CompareLeadingDigits, CompareTest4) {
//	ASSERT_FALSE(compare_leading_digits("321", "32"));
//}
//
//TEST(CompareLeadingDigits, CompareTest5) {
//	ASSERT_FALSE(compare_leading_digits("10", "1"));
//}
//
//TEST(CompareLeadingDigits, CompareTest6) {
//	ASSERT_TRUE(compare_leading_digits("6", "10"));
//}
//
//TEST(CompareLeadingDigits, CompareTest7) {
//	ASSERT_TRUE(compare_leading_digits("23", "2"));
//}
//
//TEST(CompareLeadingDigits, CompareTest8) {
//	ASSERT_TRUE(compare_leading_digits("545", "54"));
//}
//
//TEST(CompareLeadingDigits, CompareTest9) {
//	ASSERT_TRUE(compare_leading_digits("56", "565"));
//}
//
//TEST(LargestNumber, LargestTest1) {
//	vector<string> nums = {"9", "4", "6", "1", "9"};
//	ASSERT_EQ("99641", largest_number(nums));
//}
//
//TEST(LargestNumber, LargestTest2) {
//	vector<string> nums = {"21", "2"};
//	ASSERT_EQ("221", largest_number(nums));
//}

int main() {
  int n;
  std::cin >> n;
  vector<string> a(n);
  for (size_t i = 0; i < a.size(); i++) {
    std::cin >> a[i];
  }
  std::cout << largest_number(a);
}