#include <iostream>
#include <vector>

using namespace std;

void main()
{
	int iSize;
	do
	{
		cin >> iSize;
	} while (iSize <= 0);

	vector<int> iVector;
	for (size_t i = 0; i < iSize; i++)
	{
		int iCurNum;
		cin >> iCurNum;
		iVector.push_back(iCurNum);
	}

	bool bFlag = true;
	for(size_t i = 0; i < iVector.size(); i++)
		for(size_t j = i + 1; j < iVector.size(); j++)
			if (iVector.at(j) == iVector.at(i))
			{
				cout << iVector.at(i) << " ";
				iVector.erase(iVector.begin() + i);
				iVector.erase(iVector.begin() + j);

				if(bFlag)
					bFlag = false;
			}

	if (bFlag)
		cout << "No" << endl;
	else
		cout << endl;

	system("pause");
}