#include<bits/stdc++.h>
using namespace std;
map<string,bool> a;
int main()
{
	int n;
	cin>>n;
	char la=' ';
	string h;
	cin>>h;
	la=char(h[h.length()-1]);
	a[h]=true;
	for(int i=1;i<n;i++)
	{
		cin>>h;
		if(a[h] || char(h[0])!=la)
		{
			cout<<"No"<<endl;
			return 0;
		}
		la=h[h.length()-1];
		a[h]=true;
	}
	cout<<"Yes"<<endl;
	return 0;
}
