#include <bits/stdc++.h>                                                                          
                                                                                                  
using namespace std;                                                                              
                                                                                                  
#define all(x) x.begin(), x.end()                                                                 
#define rep(i, n) for (int i = 0; i < n; ++i)                                                     
#define reps(i, m, n) for (int i = m; i <= n; ++i)                                                
                                                                                                  
using i64 = long long;                                                                            
using pii = pair<i64, i64>;                                                                       
                                                                                                  
template<class A, class B>inline bool chmax(A &a, const B &b){return b > a ? a = b,1 : 0;}        
template<class A, class B>inline bool chmin(A &a, const B &b){return b < a ? a = b,1 : 0;}        
                                                                                                  
constexpr int INF = 0x3f3f3f3f;                                                                   
constexpr i64 LINF = 0x3f3f3f3f3f3f3f3fLL;                                                        
constexpr int MOD = int(1e9) + 7;                                                                 
                                                                                                  
signed main()                                                                                     
{                                                                                                 
  ios::sync_with_stdio(false);                                                                    
  cin.tie(nullptr);                                                                               
                                                                                                  
  int n;                                                                                          
  cin >> n;                                                                                       
                                                                                                  
  bool isOK = true;                                                                               
  string s[128];                                                                                  
                                                                                                  
  map<string, bool> exist;                                                                        
  rep(i, n) {                                                                                     
    cin >> s[i];                                                                                  
    if (exist[s[i]]) isOK = false;                                                                
    exist[s[i]] = true;                                                                           
  }                                                                                               
                                                                                                  
  if (!isOK) {                                                                                    
    cout << "No" << "\n";                                                                         
    return 0;                                                                                     
  }                                                                                               
                                                                                                  
  char r = s[0][s[0].length()-1];                                                                 
  for (int i = 1; i < n; ++i) {                                                                   
    if (s[i][0] != r) isOK = false;                                                               
    r = s[i][s[i].length()-1];                                                                    
  }                                                                                               
                                                                                                  
  cout << (isOK ? "Yes" : "No") << "\n";                                                          
                                                                                                  
  return 0;                                                                                       
}                                                                                                 

Measured memory_bytes: 256