import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		//List<String> list= new ArrayList<String>(Arrays.asList(s.split("")));
		//List<Integer> list=new ArrayList<Integer>();
		//Integer[] array = new Integer[m];
		int n = sc.nextInt();
		List<String> list=new ArrayList<String>();
		for(int i=0;n>i;i++) {
			String s = sc.next();
			list.add(s);
		}
		List<String> listB = new ArrayList<String>(new HashSet<>(list));
		if(listB.size()!=list.size()) {
			System.out.println("No");
			System.exit(0);
		}
		for(int i=0;list.size()-1>i;i++) {
			String s = list.get(i);
			String t = list.get(i+1);
			List<String> list_s= new ArrayList<String>(Arrays.asList(s.split("")));
			List<String> list_t= new ArrayList<String>(Arrays.asList(t.split("")));
			s = list_s.get(list_s.size()-1);
			t = list_t.get(0);
			if(!s.equals(t)) {
				System.out.println("No");
				System.exit(0);
			}
		}
		System.out.println("Yes");
	}
} import java.util.ArrayList; ArrayList java.util import java.util.Arrays; Arrays java.util import java.util.HashSet; HashSet java.util import java.util.List; List java.util import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		//List<String> list= new ArrayList<String>(Arrays.asList(s.split("")));
		//List<Integer> list=new ArrayList<Integer>();
		//Integer[] array = new Integer[m];
		int n = sc.nextInt();
		List<String> list=new ArrayList<String>();
		for(int i=0;n>i;i++) {
			String s = sc.next();
			list.add(s);
		}
		List<String> listB = new ArrayList<String>(new HashSet<>(list));
		if(listB.size()!=list.size()) {
			System.out.println("No");
			System.exit(0);
		}
		for(int i=0;list.size()-1>i;i++) {
			String s = list.get(i);
			String t = list.get(i+1);
			List<String> list_s= new ArrayList<String>(Arrays.asList(s.split("")));
			List<String> list_t= new ArrayList<String>(Arrays.asList(t.split("")));
			s = list_s.get(list_s.size()-1);
			t = list_t.get(0);
			if(!s.equals(t)) {
				System.out.println("No");
				System.exit(0);
			}
		}
		System.out.println("Yes");
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		//List<String> list= new ArrayList<String>(Arrays.asList(s.split("")));
		//List<Integer> list=new ArrayList<Integer>();
		//Integer[] array = new Integer[m];
		int n = sc.nextInt();
		List<String> list=new ArrayList<String>();
		for(int i=0;n>i;i++) {
			String s = sc.next();
			list.add(s);
		}
		List<String> listB = new ArrayList<String>(new HashSet<>(list));
		if(listB.size()!=list.size()) {
			System.out.println("No");
			System.exit(0);
		}
		for(int i=0;list.size()-1>i;i++) {
			String s = list.get(i);
			String t = list.get(i+1);
			List<String> list_s= new ArrayList<String>(Arrays.asList(s.split("")));
			List<String> list_t= new ArrayList<String>(Arrays.asList(t.split("")));
			s = list_s.get(list_s.size()-1);
			t = list_t.get(0);
			if(!s.equals(t)) {
				System.out.println("No");
				System.exit(0);
			}
		}
		System.out.println("Yes");
	} main {
		Scanner sc = new Scanner(System.in);
		//List<String> list= new ArrayList<String>(Arrays.asList(s.split("")));
		//List<Integer> list=new ArrayList<Integer>();
		//Integer[] array = new Integer[m];
		int n = sc.nextInt();
		List<String> list=new ArrayList<String>();
		for(int i=0;n>i;i++) {
			String s = sc.next();
			list.add(s);
		}
		List<String> listB = new ArrayList<String>(new HashSet<>(list));
		if(listB.size()!=list.size()) {
			System.out.println("No");
			System.exit(0);
		}
		for(int i=0;list.size()-1>i;i++) {
			String s = list.get(i);
			String t = list.get(i+1);
			List<String> list_s= new ArrayList<String>(Arrays.asList(s.split("")));
			List<String> list_t= new ArrayList<String>(Arrays.asList(t.split("")));
			s = list_s.get(list_s.size()-1);
			t = list_t.get(0);
			if(!s.equals(t)) {
				System.out.println("No");
				System.exit(0);
			}
		}
		System.out.println("Yes");
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc List<String> list=new ArrayList<String>(); list new ArrayList<String>() for(int i=0;n>i;i++) {
			String s = sc.next();
			list.add(s);
		} int i=0; int i=0; i 0 n>i n i i++ i++ i {
			String s = sc.next();
			list.add(s);
		} {
			String s = sc.next();
			list.add(s);
		} String s = sc.next(); s sc.next() sc.next sc list.add(s) list.add list s List<String> listB = new ArrayList<String>(new HashSet<>(list)); listB new ArrayList<String>(new HashSet<>(list)) if(listB.size()!=list.size()) {
			System.out.println("No");
			System.exit(0);
		} listB.size()!=list.size() listB.size() listB.size listB list.size() list.size list {
			System.out.println("No");
			System.exit(0);
		} System.out.println("No") System.out.println System.out System System.out "No" System.exit(0) System.exit System 0 for(int i=0;list.size()-1>i;i++) {
			String s = list.get(i);
			String t = list.get(i+1);
			List<String> list_s= new ArrayList<String>(Arrays.asList(s.split("")));
			List<String> list_t= new ArrayList<String>(Arrays.asList(t.split("")));
			s = list_s.get(list_s.size()-1);
			t = list_t.get(0);
			if(!s.equals(t)) {
				System.out.println("No");
				System.exit(0);
			}
		} int i=0; int i=0; i 0 list.size()-1>i list.size()-1 list.size() list.size list 1 i i++ i++ i {
			String s = list.get(i);
			String t = list.get(i+1);
			List<String> list_s= new ArrayList<String>(Arrays.asList(s.split("")));
			List<String> list_t= new ArrayList<String>(Arrays.asList(t.split("")));
			s = list_s.get(list_s.size()-1);
			t = list_t.get(0);
			if(!s.equals(t)) {
				System.out.println("No");
				System.exit(0);
			}
		} {
			String s = list.get(i);
			String t = list.get(i+1);
			List<String> list_s= new ArrayList<String>(Arrays.asList(s.split("")));
			List<String> list_t= new ArrayList<String>(Arrays.asList(t.split("")));
			s = list_s.get(list_s.size()-1);
			t = list_t.get(0);
			if(!s.equals(t)) {
				System.out.println("No");
				System.exit(0);
			}
		} String s = list.get(i); s list.get(i) list.get list i String t = list.get(i+1); t list.get(i+1) list.get list i+1 i 1 List<String> list_s= new ArrayList<String>(Arrays.asList(s.split(""))); list_s new ArrayList<String>(Arrays.asList(s.split(""))) List<String> list_t= new ArrayList<String>(Arrays.asList(t.split(""))); list_t new ArrayList<String>(Arrays.asList(t.split(""))) s = list_s.get(list_s.size()-1) s list_s.get(list_s.size()-1) list_s.get list_s list_s.size()-1 list_s.size() list_s.size list_s 1 t = list_t.get(0) t list_t.get(0) list_t.get list_t 0 if(!s.equals(t)) {
				System.out.println("No");
				System.exit(0);
			} !s.equals(t) s.equals(t) s.equals s t {
				System.out.println("No");
				System.exit(0);
			} System.out.println("No") System.out.println System.out System System.out "No" System.exit(0) System.exit System 0 System.out.println("Yes") System.out.println System.out System System.out "Yes" String[] args args public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		//List<String> list= new ArrayList<String>(Arrays.asList(s.split("")));
		//List<Integer> list=new ArrayList<Integer>();
		//Integer[] array = new Integer[m];
		int n = sc.nextInt();
		List<String> list=new ArrayList<String>();
		for(int i=0;n>i;i++) {
			String s = sc.next();
			list.add(s);
		}
		List<String> listB = new ArrayList<String>(new HashSet<>(list));
		if(listB.size()!=list.size()) {
			System.out.println("No");
			System.exit(0);
		}
		for(int i=0;list.size()-1>i;i++) {
			String s = list.get(i);
			String t = list.get(i+1);
			List<String> list_s= new ArrayList<String>(Arrays.asList(s.split("")));
			List<String> list_t= new ArrayList<String>(Arrays.asList(t.split("")));
			s = list_s.get(list_s.size()-1);
			t = list_t.get(0);
			if(!s.equals(t)) {
				System.out.println("No");
				System.exit(0);
			}
		}
		System.out.println("Yes");
	}
} public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		//List<String> list= new ArrayList<String>(Arrays.asList(s.split("")));
		//List<Integer> list=new ArrayList<Integer>();
		//Integer[] array = new Integer[m];
		int n = sc.nextInt();
		List<String> list=new ArrayList<String>();
		for(int i=0;n>i;i++) {
			String s = sc.next();
			list.add(s);
		}
		List<String> listB = new ArrayList<String>(new HashSet<>(list));
		if(listB.size()!=list.size()) {
			System.out.println("No");
			System.exit(0);
		}
		for(int i=0;list.size()-1>i;i++) {
			String s = list.get(i);
			String t = list.get(i+1);
			List<String> list_s= new ArrayList<String>(Arrays.asList(s.split("")));
			List<String> list_t= new ArrayList<String>(Arrays.asList(t.split("")));
			s = list_s.get(list_s.size()-1);
			t = list_t.get(0);
			if(!s.equals(t)) {
				System.out.println("No");
				System.exit(0);
			}
		}
		System.out.println("Yes");
	}
} Main
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		//List<String> list= new ArrayList<String>(Arrays.asList(s.split("")));
		//List<Integer> list=new ArrayList<Integer>();
		//Integer[] array = new Integer[m];
		int n = sc.nextInt();
		List<String> list=new ArrayList<String>();
		for(int i=0;n>i;i++) {
			String s = sc.next();
			list.add(s);
		}
		List<String> listB = new ArrayList<String>(new HashSet<>(list));
		if(listB.size()!=list.size()) {
			System.out.println("No");
			System.exit(0);
		}
		for(int i=0;list.size()-1>i;i++) {
			String s = list.get(i);
			String t = list.get(i+1);
			List<String> list_s= new ArrayList<String>(Arrays.asList(s.split("")));
			List<String> list_t= new ArrayList<String>(Arrays.asList(t.split("")));
			s = list_s.get(list_s.size()-1);
			t = list_t.get(0);
			if(!s.equals(t)) {
				System.out.println("No");
				System.exit(0);
			}
		}
		System.out.println("Yes");
	}
}