#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
#include <limits.h>
#include <map>
#include <set>
#include <vector>
#include <functional>
#include <algorithm>
#include <stack>
#include <list>
#include <queue>
#include <bitset>
#include <iostream>
//#include <sstream>
using namespace std;
#define all(cont) cont.begin(), cont.end()
#define rall(cont) cont.end(), cont.begin()
#define pb push_back
#define mp make_pair
#define fs first
#define sc second
#define pf printf
#define sf scanf
#define test_ fprintf(stderr, ">>>>>>>>>>>>>>>>>>>> in <<<<<<<<<<<<<<<<<<<<\n")
#define deb(x) cerr << ">>>>>>>>>>>>>>>>>>>> " << #x << " = " << x << " <<<<<<<<<<<<<<<<<<<<\n"
#define debd(x) fprintf(stderr, ">>>>>>>>>>>>>>>>>>>> %s = %d <<<<<<<<<<<<<<<<<<<<\n", #x, x)
#define debs(x) fprintf(stderr, ">>>>>>>>>>>>>>>>>>>> %s = %s <<<<<<<<<<<<<<<<<<<<\n", #x, x)
#define debll(x) fprintf(stderr, ">>>>>>>>>>>>>>>>>>>> %s = %lld <<<<<<<<<<<<<<<<<<<<\n", #x, x)
#define deblf(x) fprintf(stderr, ">>>>>>>>>>>>>>>>>>>> %s = %lf <<<<<<<<<<<<<<<<<<<<\n", #x, x)
#define fr(i, a, b) for(int i = a ; i < (int)b ; i++)
#define frr(i, a, b) for(int i = a ; i >= (int)b ; i--)
#define tr(it, var) for(__typeof(var.begin()) it = var.begin(); it != var.end(); it++)
#define trr(rit, var) for(__typeof(var.rbegin()) rit = var.rbegin(); rit != var.rend(); rit++)
#define its(x) static_cast< ostringstream & >( ( ostringstream() << dec << x ) ).str()
#define boost ios_base::sync_with_stdio(false); cin.tie(NULL)
#define ln puts("")
#define mems(a) memset(a, 0, sizeof(a))
#define has(cont, x) ((cont).find((x)) != (cont).end())
#define sz(x) ((int)(x).size())
//typedef
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<bool> vb;
typedef vector<ll> vll;
//bitmask
int on_bit(int x, int pos) {x |= (1 << pos); return x;}
int off_bit(int x, int pos) {x &= ~(1 << pos); return x;}
bool is_on_bit(int x, int pos) {return ((x & (1 << pos)) != 0);}
int flip_bit(int x, int pos) {x ^= (1 << pos); return x;}
int lsb(int x) {return x & (-x);}
int on_bit_all(int x, int pos) {x = (1 << pos)-1; return x;}
//constants
const double EPS = 1e-9;
const double PI = 2*acos(0.0);
const int INF = 0x3f3f3f3f;
const int MOD = 1e9+7;
//moves
const int dx1[] = {0, 1, 0, -1};
const int dy1[] = {1, 0, -1, 0};
const int dx2[] = {-1, -1, -1, 0, 0, 1, 1, 1};
const int dy2[] = {-1, 0, 1, -1, 1, -1, 0, 1};

ll gcd(ll a, ll b) {return b?gcd(b,a%b):a;}

int number_of_strings;

set<string> string_set;
vector<string> string_vector;

int main() {
//  freopen("C:\\Users\\user\\Desktop\\cp\\input.in", "r", stdin);
  sf("%d", &number_of_strings);
  bool ok1 = true;
  while(number_of_strings--) {
    string tmp;
    cin >> tmp;
    string_vector.push_back(tmp);
    if(has(string_set, tmp)) {
      ok1 = false;
    }
    else string_set.insert(tmp);
  }
  bool ok2 = true;
  fr(i, 0, string_vector.size() - 1) {
    string now = string_vector[i];
    string nextstr = string_vector[i+1];
    if(now[now.size() - 1] != nextstr[0]) ok2 = false;
  }
  
  puts(ok1 && ok2 ? "Yes" : "No");
  return 0;
}


Measured memory_bytes: 256