import java.util.*;

public class Main {
    static int[] arr = new int[7];
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        for (int i = 0; i < 7; i++) {
            arr[i] = sc.nextInt();
        }
        check(0, new int[7], new boolean[7]);
        System.out.println("NO");
    }
    
    static void check(int idx, int[] values, boolean[] used) {
        if (idx == 7) {
            for (int i = 0; i < 7 - 2; i++) {
                if (values[i] < values[i + 2] &&
                    ((values[i] > values[i + 1] && values[i + 2] > values[i + 1]) || (values[i] < values[i + 1] && values[i + 2] < values[i + 1]))) {
                        continue;
                }
                return;
            }
            System.out.println("YES");
            System.exit(0);
        }
        for (int i = 0; i < 7; i++) {
            if (used[i]) {
                continue;
            }
            used[i] = true;
            values[idx] = arr[i];
            check(idx + 1, values, used);
            used[i] = false;
        }
        
    }
}