#include <iostream>
#include <map>
using namespace std;
map <string,bool> mp;
int main() {
    int n;
    string l;
    cin >> n;
    for (int i=0;i<n;i++) {
        string s;
        cin >> s;
        if (i==0) l=s;
        else if (s[0]!=l[l.length()-1]||mp[s]) return cout << "No" << endl,0;
        mp[s]=true;
        l=s;
    }
    cout << "Yes" << endl;
    return 0;
}