import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.*;

public class Solution {
    public static void main(String[] args) throws IOException {
        Scanner scanner = new Scanner(new File("input.txt"));
        PrintWriter writer = new PrintWriter(new FileOutputStream("output.txt"));
        final int count = 7;
        int N = scanner.nextInt();
        boolean [] visited = new boolean[count];
        @SuppressWarnings("unchecked")
        List<Integer>[] list = new List[count];
        for (int i = 0; i < count; i++)
            list[i] = new ArrayList<Integer>();

        int v, w;
        for (int i = 0; i < N; i++)
        {
            v = scanner.nextInt();
            w = scanner.nextInt();
            if(v != w)
            {
                list[v].add(w);
                list[w].add(v);
            }
        }

        boolean flag = true;
        for(int i = 0; i < count; i++)
        {
            if ( !(list[i].size() % 2 == 0))
            {
                flag = false;
                break;
            }
        }

        if ( flag == false)
            writer.print("No");
        else {
            Queue <Integer> queue = new LinkedList<>();
            for (int i = 0; i < count; i++)
            {
                if (visited[i] == false)
                {
                    visited[i] = true;
                    queue.add(i);
                    while (!queue.isEmpty())
                    {
                        int u = queue.peek();
                        queue.poll();
                        for (int j = 0; j < list[u].size(); j++)
                        {
                            int p = list[u].get(j);
                            if(visited[p]) continue;
                            queue.add(p);
                            visited[p] = true;
                        }
                    }
                }
            }

            for (Boolean b : visited)
            {
                if ( b == false)
                {
                    flag = false;
                    break;
                }
            }

            if (flag == false)
            {
                writer.print("No");
            }
            else {
                writer.print("Yes");
            }
        }


        writer.flush();
    }
}