/**
 * Maria Sales Nš 41748 MIEI
 * Ricardo Silva Nš 37798 LEI
 */

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;


public class Main {

	public static void main(String[] args) throws NumberFormatException, IOException {
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer s;

		// Read first line
		s = new StringTokenizer(in.readLine());
		int nLocations= Integer.parseInt(s.nextToken());
		int nRoads = Integer.parseInt(s.nextToken());
		
		Graph graph = new Graph(nLocations, nRoads);
		
		// Graph construction
		for(int i = 0; i < nRoads; i++){
			s = new StringTokenizer(in.readLine());
			int v1 = Integer.parseInt(s.nextToken());
			int v2 = Integer.parseInt(s.nextToken());
			graph.addArc(v1, v2);
		}
		
		// Read last line
		s = new StringTokenizer(in.readLine());
		boolean result = graph.process(Integer.parseInt(s.nextToken()), Integer.parseInt(s.nextToken()), 
				Integer.parseInt(s.nextToken()));
		
		if(result)
			System.out.println("Yes");
		else
			System.out.println("No");
		

	}

}