content: /*
  You are given S a sequence of n integers i.e. S = s1, s2, ..., sn. Compute if it is possible to split S into two parts : s1, s2, ..., si and si+1, si+2, ….., sn (0 <= i <= n) in such a way that the first part is strictly decreasing while the second is strictly increasing one.
  Note : We say that x is strictly larger than y when x > y. So, a strictly increasing sequence can be 1 4 8. However, 1 4 4 is NOT a strictly increasing sequence.
  That is, in the sequence if numbers are decreasing, they can start increase at one point. And once number starts increasing, they cannot decrease at any point further.
  Sequence made up of only increasing numbers or only decreasing numbers is a valid sequence. So in both the cases, print true.
  You just need to print true/false. No need to split the sequence.
  
  Input format :
  Line 1 : Integer 'n'
  Line 2 and Onwards : 'n' integers on 'n' lines(single integer on each line)
  
  Output Format :
  "true" or "false" (without quotes)
  
  Constraints :
  0 <= n <= 10^7
  
  Sample Input 1 :
  5
  9
  8
  4
  5
  6
  Sample Output 1 :
  true
  
  Sample Input 2 :
  3
  1
  2
  3
  Sample Output 2 :
  true
  
  Sample Input 3 :
  3
  8
  7
  7
  Sample Output 3 :
  false
  
  Explanation for Sample Format 3 : 8 7 7 is not strictly decreasing, so output is false.
  Sample Input 4 :
  6
  8
  7
  6
  5
  8
  2
  Sample Output 4 :
  false
  
  Explanation for Sample Input 4 :
  The series is : 8 7 6 5 8 2
  It is strictly decreasing first (8 7 6 5). Then it's strictly increasing (5 8). But then it starts strictly decreasing again (8 2). Therefore, the output for this test case is 'false'
  */
  
  import java.util.*;
  public class Main {
  	
  	public static void main(String[] args) {
  		// Write your code here
          Scanner scan = new Scanner(System.in);
          int n=scan.nextInt();
          int arr[] = new int[n];
          for (int i=0;i<n;i++)
          {
              arr[i]=scan.nextInt();
          }
          boolean check=true;
          int i;
          for (i=0;i<n-1;i++)
          {
              //System.out.println("Elements compared at position "+ i + " and position "+ (i+1) + " : " + arr[i] +" " + arr[i+1]);
              if (arr[i]<=arr[i+1])
              {
                  //System.out.println("Loop for strictly decreasing broken at "+ i);
                  break;
              }
          }        
              //System.out.println("Starting loop for strictly increasing from from position "+i);
              for (int j=i;j<n-1;j++)
          	{
                  //System.out.println("Elements compared at position "+ j + " and position "+ (j+1) + " : " + arr[j] +" " + arr[j+1]);
              	if (arr[j]>=arr[j+1])
              	{
                      //System.out.println("Loop broken at "+i);
                  	check=false;
                  	break;
              	}
          	}
          System.out.println(check);    
  	}
  }
  