    #include<bits/stdc++.h>
    using namespace std;
    int n;
    char k;
    set <string> s;
    bool b;
    int main(){
    	cin>>n;
    	for(int i=0;i<n;i++){
    		string c;
    		cin>>c;
    		if(s.find(c)!=s.end() || (i!=0 && c[0]!=k))
    			b=true;
    		else
    			s.insert(c);
    		k=c[c.size()-1];
    	}
    	if(b)
    		cout<<"No";
    	else
    		cout<<"Yes";
    }