using System;
using System.Text;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
using static System.Console;
using static System.Math;

namespace ABC_practice
{
    public class Program
    {

        #region templete

        private static void WL(string s) { WriteLine(s); }

        /// <summary>
        /// 最小公倍数
        /// </summary>
        /// <param name="a"></param>
        /// <param name="b"></param>
        /// <returns></returns>
        static long Gcd(long a, long b)
        {
            var v = new[] { a, b };
            while (v[1] != 0) { v = new[] { v[1], v[0] % v[1] }; }
            return v[0];
        }
        /// <summary>
        /// 最小公約数
        /// </summary>
        /// <param name="a"></param>
        /// <param name="b"></param>
        /// <returns></returns>
        static long Lcm(long a, long b)
        {
            return a / Gcd(a, b) * b;
        }

        public static void Main(string[] args)
        {
            new Program().Solve();
            ReadLine();
        }

        #endregion

        public void Solve()
        {
            var cin = new Scanner();
            var N = cin.nextInt();
            var W = new string[N];
            for (int i = 0; i < N; i++)
            {
                W[i] = cin.next();
            }
            // 重複確認
            var N2 = W.Distinct().ToArray().Count();
            if(N != N2)
            {
                WL("No");
                return;
            }
            // i番目の単語末尾とi+1番目の単語戦闘の一致確認
            for (int i = 0; i < N-1; i++)
            {
                if (W[i].Last()!=W[i+1].First())
                {
                    WL("No");
                    return;
                }
            }
            WL("Yes");
        }
    }
}


#region console in

class Scanner
{
    string[] s;
    int i;

    char[] cs = new char[] { ' ' };

    public Scanner()
    {
        s = new string[0];
        i = 0;
    }

    public string next()
    {
        if (i < s.Length) return s[i++];
        string st = Console.ReadLine();
        while (st == "") st = Console.ReadLine();
        s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
        if (s.Length == 0) return next();
        i = 0;
        return s[i++];
    }

    public int nextInt()
    {
        return int.Parse(next());
    }
    public int[] ArrayInt(int N, int add = 0)
    {
        int[] Array = new int[N];
        for (int i = 0; i < N; i++)
        {
            Array[i] = nextInt() + add;
        }
        return Array;
    }

    public long nextLong()
    {
        return long.Parse(next());
    }

    public long[] ArrayLong(int N, long add = 0)
    {
        long[] Array = new long[N];
        for (int i = 0; i < N; i++)
        {
            Array[i] = nextLong() + add;
        }
        return Array;
    }

    public double nextDouble()
    {
        return double.Parse(next());
    }


    public double[] ArrayDouble(int N, double add = 0)
    {
        double[] Array = new double[N];
        for (int i = 0; i < N; i++)
        {
            Array[i] = nextDouble() + add;
        }
        return Array;
    }
}

#endregion

Measured memory_bytes: 11356