#include <iostream>
#include <string>
using namespace std;

int main()
{
	int n;
	while (cin >> n)
	{
		int a[7] = {0};
		string s;
		for (int i=0; i<n; i++)
		{
			cin >> s;
			a[s[0]-'0']++;
			a[s[1]-'0']++;
		}

		int odd=0;
		for (int i=0; i<7; i++)
			if (a[i]%2)
				odd++;

		cout << ((odd==0||odd==2) ? "Yes" : "No") << endl;
	}
}