package No400番台;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Random;
import java.util.Scanner;
public class Main {
	static InputStream is;
	static PrintWriter out;
	static String INPUT = "";


	public static void main(String[] args) throws Exception
	{
		is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
		out = new PrintWriter(System.out);

		solver();
		out.flush();
	}

	static long nl()
	{
		try {
			long num = 0;
			boolean minus = false;
			while((num = is.read()) != -1 && !((num >= '0' && num <= '9') || num == '-'));
			if(num == '-'){
				num = 0;
				minus = true;
			}else{
				num -= '0';
			}

			while(true){
				int b = is.read();
				if(b >= '0' && b <= '9'){
					num = num * 10 + (b - '0');
				}else{
					return minus ? -num : num;
				}
			}
		} catch (IOException e) {
		}
		return -1;
	}

	static char nc()
	{
		try {
			int b = skip();
			if(b == -1)return 0;
			return (char)b;
		} catch (IOException e) {
		}
		return 0;
	}

	static double nd()
	{
		try {
			return Double.parseDouble(ns());
		}catch(Exception e) {
		}
		return 0;
	}

	static String ns()
	{
		try{
			int b = skip();
			StringBuilder sb = new StringBuilder();
			if(b == -1)return "";
			sb.append((char)b);
			while(true){
				b = is.read();
				if(b == -1)return sb.toString();
				if(b <= ' ')return sb.toString();
				sb.append((char)b);
			}
		} catch (IOException e) {
		}
		return "";
	}

	public static char[] ns(int n)
	{
		char[] buf = new char[n];
		try{
			int b = skip(), p = 0;
			if(b == -1)return null;
			buf[p++] = (char)b;
			while(p < n){
				b = is.read();
				if(b == -1 || b <= ' ')break;
				buf[p++] = (char)b;
			}
			return Arrays.copyOf(buf, p);
		} catch (IOException e) {
		}
		return null;
	}

	public static byte[] nse(int n)
	{
		byte[] buf = new byte[n];
		try{
			int b = skip();
			if(b == -1)return null;
			is.read(buf);
			return buf;
		} catch (IOException e) {
		}
		return null;
	}

	static int skip() throws IOException
	{
		int b;
		while((b = is.read()) != -1 && !(b >= 33 && b <= 126));
		return b;
	}

	static boolean eof()
	{
		try {
			is.mark(1000);
			int b = skip();
			is.reset();
			return b == -1;
		} catch (IOException e) {
			return true;
		}
	}

	static int ni()
	{
		try {
			int num = 0;
			boolean minus = false;
			while((num = is.read()) != -1 && !((num >= '0' && num <= '9') || num == '-'));
			if(num == '-'){
				num = 0;
				minus = true;
			}else{
				num -= '0';
			}

			while(true){
				int b = is.read();
				if(b >= '0' && b <= '9'){
					num = num * 10 + (b - '0');
				}else{
					return minus ? -num : num;
				}
			}
		} catch (IOException e) {
		}
		return -1;
	}

	static void solver() {
		Scanner sc = new Scanner(System.in);
		int n = ni();
		int m = ni();
		ArrayList<Integer>[] e = new ArrayList[n];
		for (int i = 0; i < n; i++) {
			e[i] = new ArrayList<>();
		}
		for (int i = 0; i < m; i++) {
			int a =ni() - 1;
			int b = ni() - 1;
			e[a].add(b);
			e[b].add(a);
		}

		boolean ans = false;
		for (int i = 0; i < 100; i++) {
			Random rand = new Random();
			int[] col = new int[n];
			Arrays.fill(col, -1);
			for (int j = 1; j < n; j++) {
				col[j] = rand.nextInt(4);
			}
			boolean[][] dp = new boolean[1 << 4][n];
			dp[0][0] = true;
			for (int s = 0; s < (1 << 4) - 1; s++) {
				for (int v = 0; v < n; v++) {
					if (dp[s][v]) {
						for (int u : e[v]) {
							if (u != 0) {
								int t = s | (1 << col[u]);
								if (t > s) {
									dp[t][u] = true;
								}
							}
						}
					}
				}
			}
			for (int j = 1; j < n; j++) {
				if (dp[(1 << 4) - 1][j]) {
					for (int v : e[j]) {
						if (v == 0) {
							ans = true;
						}
					}
				}
			}
		}
		out.println(ans ? "YES" : "NO");
	}
}