public static void main ( String [ ] args ) {
  Scanner scanner = new Scanner ( System . in ) ;
  int n = scanner . nextInt ( ) ;
  int [ ] [ ] coo = new int [ n ] [ 2 ] ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    coo [ i ] [ 0 ] = scanner . nextInt ( ) ;
    coo [ i ] [ 1 ] = scanner . nextInt ( ) ;
  }
  if ( n == 1 ) {
    System . out . println ( - 1 ) ;
  }
  else if ( n == 2 ) {
    int side1 = Math . abs ( coo [ 0 ] [ 1 ] - coo [ 1 ] [ 1 ] ) ;
    int side2 = Math . abs ( coo [ 0 ] [ 0 ] - coo [ 1 ] [ 0 ] ) ;
    if ( side1 == 0 || side2 == 0 ) {
      System . out . println ( - 1 ) ;
    }
    else {
      System . out . println ( side1 * side2 ) ;
    }
  }
  else {
    int side1 = 0 ;
    int side2 = 0 ;
    for ( int i = 0 ;
    i < 2 ;
    i ++ ) {
      if ( coo [ i ] [ 1 ] - coo [ i + 1 ] [ 1 ] != 0 ) side2 = Math . abs ( coo [ i ] [ 1 ] - coo [ i + 1 ] [ 1 ] ) ;
      if ( coo [ i ] [ 0 ] - coo [ i + 1 ] [ 0 ] != 0 ) side1 = Math . abs ( coo [ i ] [ 0 ] - coo [ i + 1 ] [ 0 ] ) ;
    }
    System . out . println ( side1 * side2 ) ;
  }
}

public static void main ( String [ ] args ) { Scanner scanner = new Scanner ( System . in ) ; int n = scanner . nextInt ( ) ; int [ ] [ ] coo = new int [ n ] [ 2 ] ; for ( int i = 0 ; i < n ; i ++ ) { coo [ i ] [ 0 ] = scanner . nextInt ( ) ; coo [ i ] [ 1 ] = scanner . nextInt ( ) ; } if ( n == 1 ) { System . out . println ( - 1 ) ; } else if ( n == 2 ) { int side1 = Math . abs ( coo [ 0 ] [ 1 ] - coo [ 1 ] [ 1 ] ) ; int side2 = Math . abs ( coo [ 0 ] [ 0 ] - coo [ 1 ] [ 0 ] ) ; if ( side1 == 0 || side2 == 0 ) { System . out . println ( - 1 ) ; } else { System . out . println ( side1 * side2 ) ; } } else { int side1 = 0 ; int side2 = 0 ; for ( int i = 0 ; i < 2 ; i ++ ) { if ( coo [ i ] [ 1 ] - coo [ i + 1 ] [ 1 ] != 0 ) side2 = Math . abs ( coo [ i ] [ 1 ] - coo [ i + 1 ] [ 1 ] ) ; if ( coo [ i ] [ 0 ] - coo [ i + 1 ] [ 0 ] != 0 ) side1 = Math . abs ( coo [ i ] [ 0 ] - coo [ i + 1 ] [ 0 ] ) ; } System . out . println ( side1 * side2 ) ; } }
(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)) dimensions: (dimensions_expr (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: (array_access array: (identifier) index: (identifier)) index: (decimal_integer_literal)) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (expression_statement (assignment_expression left: (array_access array: (array_access array: (identifier) index: (identifier)) index: (decimal_integer_literal)) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))))) (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (unary_expression operand: (decimal_integer_literal)))))) alternative: (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))) consequence: (block (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (array_access array: (array_access array: (identifier) index: (decimal_integer_literal)) index: (decimal_integer_literal)) right: (array_access array: (array_access array: (identifier) index: (decimal_integer_literal)) index: (decimal_integer_literal))))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (array_access array: (array_access array: (identifier) index: (decimal_integer_literal)) index: (decimal_integer_literal)) right: (array_access array: (array_access array: (identifier) index: (decimal_integer_literal)) index: (decimal_integer_literal))))))) (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (binary_expression left: (identifier) right: (decimal_integer_literal)))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (unary_expression operand: (decimal_integer_literal)))))) alternative: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (identifier)))))))) alternative: (block (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (local_variable_declaration type: (integral_type) 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: (decimal_integer_literal)) update: (update_expression (identifier)) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (array_access array: (array_access array: (identifier) index: (identifier)) index: (decimal_integer_literal)) right: (array_access array: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (decimal_integer_literal))) index: (decimal_integer_literal))) right: (decimal_integer_literal))) consequence: (expression_statement (assignment_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (array_access array: (array_access array: (identifier) index: (identifier)) index: (decimal_integer_literal)) right: (array_access array: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (decimal_integer_literal))) index: (decimal_integer_literal)))))))) (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (array_access array: (array_access array: (identifier) index: (identifier)) index: (decimal_integer_literal)) right: (array_access array: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (decimal_integer_literal))) index: (decimal_integer_literal))) right: (decimal_integer_literal))) consequence: (expression_statement (assignment_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (array_access array: (array_access array: (identifier) index: (identifier)) index: (decimal_integer_literal)) right: (array_access array: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (decimal_integer_literal))) index: (decimal_integer_literal)))))))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (identifier))))))))))