public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  int n = sc . nextInt ( ) ;
  int [ ] a = new int [ n ] ;
  int maxi = 0 , max = 0 ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    a [ i ] = sc . nextInt ( ) ;
    if ( a [ i ] > max ) {
      maxi = i ;
      max = a [ i ] ;
    }
  }
  boolean f = true ;
  for ( int i = maxi - 1 , j = maxi + 1 ;
  i >= 0 || j < n ;
  i -- , j ++ ) {
    if ( i >= 0 && a [ i ] > a [ i + 1 ] ) {
      f = false ;
      break ;
    }
    if ( j < n && a [ j ] > a [ j - 1 ] ) {
      f = false ;
      break ;
    }
  }
  if ( f ) {
    System . out . println ( "YES" ) ;
  }
  else {
    System . out . println ( "NO" ) ;
  }
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; int n = sc . nextInt ( ) ; int [ ] a = new int [ n ] ; int maxi = 0 , max = 0 ; for ( int i = 0 ; i < n ; i ++ ) { a [ i ] = sc . nextInt ( ) ; if ( a [ i ] > max ) { maxi = i ; max = a [ i ] ; } } boolean f = true ; for ( int i = maxi - 1 , j = maxi + 1 ; i >= 0 || j < n ; i -- , j ++ ) { if ( i >= 0 && a [ i ] > a [ i + 1 ] ) { f = false ; break ; } if ( j < n && a [ j ] > a [ j - 1 ] ) { f = false ; break ; } } if ( f ) { System . out . println ( " YES " ) ; } else { System . out . println ( " NO " ) ; } }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (array_type element: (type_identifier) dimensions: (dimensions)) name: (identifier))) body: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (type_identifier) arguments: (argument_list (field_access object: (identifier) field: (identifier)))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (local_variable_declaration type: (array_type element: (integral_type) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (array_creation_expression type: (integral_type) dimensions: (dimensions_expr (identifier))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal)) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (expression_statement (assignment_expression left: (array_access array: (identifier) index: (identifier)) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (if_statement condition: (parenthesized_expression (binary_expression left: (array_access array: (identifier) index: (identifier)) right: (identifier))) consequence: (block (expression_statement (assignment_expression left: (identifier) right: (identifier))) (expression_statement (assignment_expression left: (identifier) right: (array_access array: (identifier) index: (identifier)))))))) (local_variable_declaration type: (boolean_type) declarator: (variable_declarator name: (identifier) value: (true))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (identifier) right: (decimal_integer_literal))) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (identifier) right: (decimal_integer_literal)))) condition: (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (binary_expression left: (identifier) right: (identifier))) update: (update_expression (identifier)) update: (update_expression (identifier)) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (binary_expression left: (array_access array: (identifier) index: (identifier)) right: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (decimal_integer_literal)))))) consequence: (block (expression_statement (assignment_expression left: (identifier) right: (false))) (break_statement))) (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (identifier)) right: (binary_expression left: (array_access array: (identifier) index: (identifier)) right: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (decimal_integer_literal)))))) consequence: (block (expression_statement (assignment_expression left: (identifier) right: (false))) (break_statement))))) (if_statement condition: (parenthesized_expression (identifier)) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal))))) alternative: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal))))))))