Toad Ivan has m pairs of integers, each integer is between 1 and n, inclusive. The pairs are (a_1, b_1), (a_2, b_2), …, (a_m, b_m). 

He asks you to check if there exist two integers x and y (1 ≤ x < y ≤ n) such that in each given pair at least one integer is equal to x or y.

Input

The first line contains two space-separated integers n and m (2 ≤ n ≤ 300 000, 1 ≤ m ≤ 300 000) — the upper bound on the values of integers in the pairs, and the number of given pairs.

The next m lines contain two integers each, the i-th of them contains two space-separated integers a_i and b_i (1 ≤ a_i, b_i ≤ n, a_i ≠ b_i) — the integers in the i-th pair.

Output

Output "YES" if there exist two integers x and y (1 ≤ x < y ≤ n) such that in each given pair at least one integer is equal to x or y. Otherwise, print "NO". You can print each letter in any case (upper or lower).

Examples

Input


4 6
1 2
1 3
1 4
2 3
2 4
3 4


Output


NO


Input


5 4
1 2
2 3
3 4
4 5


Output


YES


Input


300000 5
1 2
1 2
1 2
1 2
1 2


Output


YES

Note

In the first example, you can't choose any x, y because for each such pair you can find a given pair where both numbers are different from chosen integers.

In the second example, you can choose x=2 and y=4.

In the third example, you can choose x=1 and y=2.
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.HashSet;
import java.util.StringTokenizer;

public class Main {
    static InputReader in;
    static PrintWriter out;

    public static void main(String args[]) throws IOException {
        in = new InputReader();
        out = new PrintWriter(System.out);
        int t = 1;
//        t = in.nextInt()
        for (int i = 0; i < t; i++) {
            solve();
        }
        out.close();
    }

    private static void solve() throws IOException {
        int n = in.nextInt();
        int m = in.nextInt();
        int[] cnt = new int[n + 1];
        int[][] a = new int[m][2];
        for (int i = 0; i < m; ++i) {
            for (int j = 0; j < 2; ++j) {
                a[i][j] = in.nextInt();
            }
        }
        ArrayList<int[]> possible = new ArrayList<>();
        for (int i = 0; i < m; ++i) {
            boolean can = true;
            for (int[] x : possible) {
                if (match(x, a[i])) {
                    can = false;
                    break;
                }
            }
            if (can) possible.add(a[i]);
//            printltList(possible);
            if (possible.size() > 2) {
                out.println("NO");
                return;
            }
        }
        if (can(possible, a))
            out.println("YES");
        else out.println("NO");
    }

    private static boolean can(ArrayList<int[]> possible, int[][] a) {
        HashSet<Integer> w = new HashSet<>();
        for (int[] x : possible) for (int y : x) w.add(y);
        for (int x : w)
            for (int y : w) {
                int ct = 0;
                for (int[] ints : a) {
                    if (match(ints, new int[]{x, y})) ++ct;
                }
                if (ct == a.length) return true;
            }
        return false;
    }

    private static void printList(ArrayList<int[]> possible) {
        for (int[] x : possible) out.println(Arrays.toString(x) + " ");
        out.println();
    }

    private static boolean match(int[] x, int[] y) {
        for (int a : x) {
            for (int b : y) if (a == b) return true;
        }
        return false;
    }

    static class InputReader {
        BufferedReader br;
        StringTokenizer st;

        public InputReader() {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        long nextLong() {
            return Long.parseLong(next());
        }

        double nextDouble() {
            return Double.parseDouble(next());
        }

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
    }
}