#include <iostream>
#include "stdio.h"
#include "math.h"
#include "ctype.h"
#include "memory.h"
#include "string"
#include "algorithm"
using namespace std;
int main(int argc, char *argv[])
{
	int n;
	cin>>n;
	string aa[100];
	int flag = 0;
	for(int i = 0;i<n;i++)
	{
		string s;
		cin>>s;
		for(int j = 0;j< i;j++)
		{
			if(aa[j] == s)
			{
				flag =1;
			}
			if (i != 0 && s[0] != aa[i -1][aa[i-1].length() - 1])
			{
				flag = 1;
			}
		}
		aa[i] = s;
	}

	if (flag)
	{
		cout<<"No"<<endl;
	}
	else
	{
		cout<<"Yes"<<endl;
	}
	return 0;
}