import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		//int array[] = new int [N];
		int tmp1 = sc.nextInt();
		int count = 0;
		int check1 = 0;
		int check2 = 0;
		int last = 0;
		int first = 0;
		int flag = 0;
		//int check1 = new int[3];
		//int check2 = new int[3];
		for(int i = 0; i < N-1; i++) {
			int tmp2 = sc.nextInt();
			if(tmp1 > tmp2 ) {
				count++;
				if(flag == 0) {
					check1 = tmp2;
					first = tmp1;
					flag++;
				}
				check2 = tmp1;
				last = tmp2;
				if(count>=3) {
					break;
				}
			}
			tmp1 = tmp2;
		}

		if(count==1 || count>=3) {
			System.out.println("NO");
		}else if(check1<=last && count!=0) {
			System.out.println("NO");
		}else if(check2>=first && count!=0) {
			System.out.println("NO");
		}else {
			System.out.println("YES");
		}



	}

} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		//int array[] = new int [N];
		int tmp1 = sc.nextInt();
		int count = 0;
		int check1 = 0;
		int check2 = 0;
		int last = 0;
		int first = 0;
		int flag = 0;
		//int check1 = new int[3];
		//int check2 = new int[3];
		for(int i = 0; i < N-1; i++) {
			int tmp2 = sc.nextInt();
			if(tmp1 > tmp2 ) {
				count++;
				if(flag == 0) {
					check1 = tmp2;
					first = tmp1;
					flag++;
				}
				check2 = tmp1;
				last = tmp2;
				if(count>=3) {
					break;
				}
			}
			tmp1 = tmp2;
		}

		if(count==1 || count>=3) {
			System.out.println("NO");
		}else if(check1<=last && count!=0) {
			System.out.println("NO");
		}else if(check2>=first && count!=0) {
			System.out.println("NO");
		}else {
			System.out.println("YES");
		}



	}

} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		//int array[] = new int [N];
		int tmp1 = sc.nextInt();
		int count = 0;
		int check1 = 0;
		int check2 = 0;
		int last = 0;
		int first = 0;
		int flag = 0;
		//int check1 = new int[3];
		//int check2 = new int[3];
		for(int i = 0; i < N-1; i++) {
			int tmp2 = sc.nextInt();
			if(tmp1 > tmp2 ) {
				count++;
				if(flag == 0) {
					check1 = tmp2;
					first = tmp1;
					flag++;
				}
				check2 = tmp1;
				last = tmp2;
				if(count>=3) {
					break;
				}
			}
			tmp1 = tmp2;
		}

		if(count==1 || count>=3) {
			System.out.println("NO");
		}else if(check1<=last && count!=0) {
			System.out.println("NO");
		}else if(check2>=first && count!=0) {
			System.out.println("NO");
		}else {
			System.out.println("YES");
		}



	} main {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		//int array[] = new int [N];
		int tmp1 = sc.nextInt();
		int count = 0;
		int check1 = 0;
		int check2 = 0;
		int last = 0;
		int first = 0;
		int flag = 0;
		//int check1 = new int[3];
		//int check2 = new int[3];
		for(int i = 0; i < N-1; i++) {
			int tmp2 = sc.nextInt();
			if(tmp1 > tmp2 ) {
				count++;
				if(flag == 0) {
					check1 = tmp2;
					first = tmp1;
					flag++;
				}
				check2 = tmp1;
				last = tmp2;
				if(count>=3) {
					break;
				}
			}
			tmp1 = tmp2;
		}

		if(count==1 || count>=3) {
			System.out.println("NO");
		}else if(check1<=last && count!=0) {
			System.out.println("NO");
		}else if(check2>=first && count!=0) {
			System.out.println("NO");
		}else {
			System.out.println("YES");
		}



	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc int tmp1 = sc.nextInt(); tmp1 sc.nextInt() sc.nextInt sc int count = 0; count 0 int check1 = 0; check1 0 int check2 = 0; check2 0 int last = 0; last 0 int first = 0; first 0 int flag = 0; flag 0 for(int i = 0; i < N-1; i++) {
			int tmp2 = sc.nextInt();
			if(tmp1 > tmp2 ) {
				count++;
				if(flag == 0) {
					check1 = tmp2;
					first = tmp1;
					flag++;
				}
				check2 = tmp1;
				last = tmp2;
				if(count>=3) {
					break;
				}
			}
			tmp1 = tmp2;
		} int i = 0; int i = 0; i 0 i < N-1 i N-1 N 1 i++ i++ i {
			int tmp2 = sc.nextInt();
			if(tmp1 > tmp2 ) {
				count++;
				if(flag == 0) {
					check1 = tmp2;
					first = tmp1;
					flag++;
				}
				check2 = tmp1;
				last = tmp2;
				if(count>=3) {
					break;
				}
			}
			tmp1 = tmp2;
		} {
			int tmp2 = sc.nextInt();
			if(tmp1 > tmp2 ) {
				count++;
				if(flag == 0) {
					check1 = tmp2;
					first = tmp1;
					flag++;
				}
				check2 = tmp1;
				last = tmp2;
				if(count>=3) {
					break;
				}
			}
			tmp1 = tmp2;
		} int tmp2 = sc.nextInt(); tmp2 sc.nextInt() sc.nextInt sc if(tmp1 > tmp2 ) {
				count++;
				if(flag == 0) {
					check1 = tmp2;
					first = tmp1;
					flag++;
				}
				check2 = tmp1;
				last = tmp2;
				if(count>=3) {
					break;
				}
			} tmp1 > tmp2 tmp1 tmp2 {
				count++;
				if(flag == 0) {
					check1 = tmp2;
					first = tmp1;
					flag++;
				}
				check2 = tmp1;
				last = tmp2;
				if(count>=3) {
					break;
				}
			} count++ count if(flag == 0) {
					check1 = tmp2;
					first = tmp1;
					flag++;
				} flag == 0 flag 0 {
					check1 = tmp2;
					first = tmp1;
					flag++;
				} check1 = tmp2 check1 tmp2 first = tmp1 first tmp1 flag++ flag check2 = tmp1 check2 tmp1 last = tmp2 last tmp2 if(count>=3) {
					break;
				} count>=3 count 3 {
					break;
				} break; tmp1 = tmp2 tmp1 tmp2 if(count==1 || count>=3) {
			System.out.println("NO");
		}else if(check1<=last && count!=0) {
			System.out.println("NO");
		}else if(check2>=first && count!=0) {
			System.out.println("NO");
		}else {
			System.out.println("YES");
		} count==1 || count>=3 count==1 count 1 count>=3 count 3 {
			System.out.println("NO");
		} System.out.println("NO") System.out.println System.out System System.out "NO" if(check1<=last && count!=0) {
			System.out.println("NO");
		}else if(check2>=first && count!=0) {
			System.out.println("NO");
		}else {
			System.out.println("YES");
		} check1<=last && count!=0 check1<=last check1 last count!=0 count 0 {
			System.out.println("NO");
		} System.out.println("NO") System.out.println System.out System System.out "NO" if(check2>=first && count!=0) {
			System.out.println("NO");
		}else {
			System.out.println("YES");
		} check2>=first && count!=0 check2>=first check2 first count!=0 count 0 {
			System.out.println("NO");
		} System.out.println("NO") System.out.println System.out System System.out "NO" {
			System.out.println("YES");
		} System.out.println("YES") System.out.println System.out System System.out "YES" String[] args args public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		//int array[] = new int [N];
		int tmp1 = sc.nextInt();
		int count = 0;
		int check1 = 0;
		int check2 = 0;
		int last = 0;
		int first = 0;
		int flag = 0;
		//int check1 = new int[3];
		//int check2 = new int[3];
		for(int i = 0; i < N-1; i++) {
			int tmp2 = sc.nextInt();
			if(tmp1 > tmp2 ) {
				count++;
				if(flag == 0) {
					check1 = tmp2;
					first = tmp1;
					flag++;
				}
				check2 = tmp1;
				last = tmp2;
				if(count>=3) {
					break;
				}
			}
			tmp1 = tmp2;
		}

		if(count==1 || count>=3) {
			System.out.println("NO");
		}else if(check1<=last && count!=0) {
			System.out.println("NO");
		}else if(check2>=first && count!=0) {
			System.out.println("NO");
		}else {
			System.out.println("YES");
		}



	}

} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		//int array[] = new int [N];
		int tmp1 = sc.nextInt();
		int count = 0;
		int check1 = 0;
		int check2 = 0;
		int last = 0;
		int first = 0;
		int flag = 0;
		//int check1 = new int[3];
		//int check2 = new int[3];
		for(int i = 0; i < N-1; i++) {
			int tmp2 = sc.nextInt();
			if(tmp1 > tmp2 ) {
				count++;
				if(flag == 0) {
					check1 = tmp2;
					first = tmp1;
					flag++;
				}
				check2 = tmp1;
				last = tmp2;
				if(count>=3) {
					break;
				}
			}
			tmp1 = tmp2;
		}

		if(count==1 || count>=3) {
			System.out.println("NO");
		}else if(check1<=last && count!=0) {
			System.out.println("NO");
		}else if(check2>=first && count!=0) {
			System.out.println("NO");
		}else {
			System.out.println("YES");
		}



	}

} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		//int array[] = new int [N];
		int tmp1 = sc.nextInt();
		int count = 0;
		int check1 = 0;
		int check2 = 0;
		int last = 0;
		int first = 0;
		int flag = 0;
		//int check1 = new int[3];
		//int check2 = new int[3];
		for(int i = 0; i < N-1; i++) {
			int tmp2 = sc.nextInt();
			if(tmp1 > tmp2 ) {
				count++;
				if(flag == 0) {
					check1 = tmp2;
					first = tmp1;
					flag++;
				}
				check2 = tmp1;
				last = tmp2;
				if(count>=3) {
					break;
				}
			}
			tmp1 = tmp2;
		}

		if(count==1 || count>=3) {
			System.out.println("NO");
		}else if(check1<=last && count!=0) {
			System.out.println("NO");
		}else if(check2>=first && count!=0) {
			System.out.println("NO");
		}else {
			System.out.println("YES");
		}



	}

}