public static void main ( String [ ] $ ) {
  Scanner s = new Scanner ( System . in ) ;
  int n = s . nextInt ( ) ;
  Point [ ] p = new Point [ n ] ;
  Arrays . setAll ( p , o -> new Point ( s . nextInt ( ) , s . nextInt ( ) ) ) ;
  int r = 0 ;
  for ( int i = 0 ;
  i < n ;
  ++ i ) {
    Point a = p [ i ] ;
    for ( int j = i + 1 ;
    j < n ;
    ++ j ) {
      Point b = p [ j ] ;
      for ( int k = j + 1 ;
      k < n ;
      ++ k ) {
        Point c = p [ k ] ;
        if ( Math . atan2 ( a . y - b . y , a . x - b . x ) != Math . atan2 ( a . y - c . y , a . x - c . x ) && ( f ( a , b ) + f ( b , c ) + f ( c , a ) ) % 2 == 0 ) ++ r ;
      }
    }
  }
  System . out . println ( r ) ;
}

public static void main ( String [ ] $ ) { Scanner s = new Scanner ( System . in ) ; int n = s . nextInt ( ) ; Point [ ] p = new Point [ n ] ; Arrays . setAll ( p , o -> new Point ( s . nextInt ( ) , s . nextInt ( ) ) ) ; int r = 0 ; for ( int i = 0 ; i < n ; ++ i ) { Point a = p [ i ] ; for ( int j = i + 1 ; j < n ; ++ j ) { Point b = p [ j ] ; for ( int k = j + 1 ; k < n ; ++ k ) { Point c = p [ k ] ; if ( Math . atan2 ( a . y - b . y , a . x - b . x ) != Math . atan2 ( a . y - c . y , a . x - c . x ) && ( f ( a , b ) + f ( b , c ) + f ( c , a ) ) % 2 == 0 ) ++ r ; } } } System . out . println ( r ) ; }
(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: (type_identifier) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (array_creation_expression type: (type_identifier) dimensions: (dimensions_expr (identifier))))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (lambda_expression parameters: (identifier) body: (object_creation_expression type: (type_identifier) arguments: (argument_list (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))))))) (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: (identifier)) update: (update_expression (identifier)) body: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (array_access array: (identifier) index: (identifier)))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (identifier) right: (decimal_integer_literal)))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (array_access array: (identifier) index: (identifier)))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (identifier) right: (decimal_integer_literal)))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (array_access array: (identifier) index: (identifier)))) (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (field_access object: (identifier) field: (identifier)) right: (field_access object: (identifier) field: (identifier))) (binary_expression left: (field_access object: (identifier) field: (identifier)) right: (field_access object: (identifier) field: (identifier))))) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (field_access object: (identifier) field: (identifier)) right: (field_access object: (identifier) field: (identifier))) (binary_expression left: (field_access object: (identifier) field: (identifier)) right: (field_access object: (identifier) field: (identifier)))))) right: (binary_expression left: (binary_expression left: (parenthesized_expression (binary_expression left: (binary_expression left: (method_invocation name: (identifier) arguments: (argument_list (identifier) (identifier))) right: (method_invocation name: (identifier) arguments: (argument_list (identifier) (identifier)))) right: (method_invocation name: (identifier) arguments: (argument_list (identifier) (identifier))))) right: (decimal_integer_literal)) right: (decimal_integer_literal)))) consequence: (expression_statement (update_expression (identifier)))))))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier))))))