public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  long n = sc . nextLong ( ) ;
  long m = sc . nextLong ( ) ;
  int a = sc . nextInt ( ) ;
  int b = sc . nextInt ( ) ;
  if ( n % m == 0 ) {
    System . out . println ( "0" ) ;
  }
  else {
    if ( n > m ) {
      long div = n / m ;
      long temp = n - m * div ;
      long cost1 = temp * b ;
      div ++ ;
      long temp1 = m * div - n ;
      long cost2 = temp1 * a ;
      if ( cost1 > cost2 ) {
        System . out . println ( cost2 ) ;
      }
      else {
        System . out . println ( cost1 ) ;
      }
    }
    else {
      long cost1 = n * b ;
      long cost2 = ( m - n ) * a ;
      if ( cost1 > cost2 ) {
        System . out . println ( cost2 ) ;
      }
      else {
        System . out . println ( cost1 ) ;
      }
    }
  }
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; long n = sc . nextLong ( ) ; long m = sc . nextLong ( ) ; int a = sc . nextInt ( ) ; int b = sc . nextInt ( ) ; if ( n % m == 0 ) { System . out . println ( "0" ) ; } else { if ( n > m ) { long div = n / m ; long temp = n - m * div ; long cost1 = temp * b ; div ++ ; long temp1 = m * div - n ; long cost2 = temp1 * a ; if ( cost1 > cost2 ) { System . out . println ( cost2 ) ; } else { System . out . println ( cost1 ) ; } } else { long cost1 = n * b ; long cost2 = ( m - n ) * a ; if ( cost1 > cost2 ) { System . out . println ( cost2 ) ; } else { System . out . println ( cost1 ) ; } } } }
(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: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (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: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (identifier)) right: (decimal_integer_literal))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal))))) alternative: (block (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) consequence: (block (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (identifier) right: (identifier)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (identifier) right: (binary_expression left: (identifier) right: (identifier))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (identifier) right: (identifier)))) (expression_statement (update_expression (identifier))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (binary_expression left: (identifier) right: (identifier)) right: (identifier)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (identifier) right: (identifier)))) (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier))))) alternative: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier))))))) alternative: (block (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (identifier) right: (identifier)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) right: (identifier)))) (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier))))) alternative: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier))))))))))))