import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.*;

public class Main {

    static BufferedReader in;
    static PrintWriter out;
    static StringTokenizer tok;

    void solve() throws IOException {
        int[] d = nia(7);
        boolean can = dfs(d, new int[7], 0);
        out.println(can ? "YES" : "NO");
    }

    boolean dfs(int[] d, int[] a, int used) {
        int n = Integer.bitCount(used);
        if (n == 7) {
            for (int i = 0; i < 5; i++) {
                if (a[i] <= a[i + 1] && a[i + 1] <= a[i + 2] || a[i] >= a[i + 1] && a[i + 1] >= a[i + 2] || a[i] >= a[i + 2]) {
                    return false;
                }
            }

            return true;
        }

        for (int i = 0; i < 7; i++) {
            if ((used >> i & 1) == 0) {
                a[n] = d[i];
                if (dfs(d, a, used | 1 << i)) {
                    return true;
                }
            }
        }

        return false;
    }

    String ns() throws IOException {
        while (!tok.hasMoreTokens()) {
            tok = new StringTokenizer(in.readLine(), " ");
        }
        return tok.nextToken();
    }

    int ni() throws IOException {
        return Integer.parseInt(ns());
    }

    long nl() throws IOException {
        return Long.parseLong(ns());
    }

    double nd() throws IOException {
        return Double.parseDouble(ns());
    }

    String[] nsa(int n) throws IOException {
        String[] res = new String[n];
        for (int i = 0; i < n; i++) {
            res[i] = ns();
        }
        return res;
    }

    int[] nia(int n) throws IOException {
        int[] res = new int[n];
        for (int i = 0; i < n; i++) {
            res[i] = ni();
        }
        return res;
    }

    long[] nla(int n) throws IOException {
        long[] res = new long[n];
        for (int i = 0; i < n; i++) {
            res[i] = nl();
        }
        return res;
    }

    public static void main(String[] args) throws IOException {
        in = new BufferedReader(new InputStreamReader(System.in));
        out = new PrintWriter(System.out);
        tok = new StringTokenizer("");
        Main main = new Main();
        main.solve();
        out.close();
    }
}