public static void main ( String [ ] args ) {
  Scanner input = new Scanner ( System . in ) ;
  long n = input . nextLong ( ) ;
  long m = input . nextLong ( ) ;
  int a = input . nextInt ( ) ;
  int b = input . nextInt ( ) ;
  if ( n % m == 0 ) {
    System . out . println ( 0 ) ;
  }
  else {
    if ( n < m ) {
      System . out . println ( Math . min ( ( m - n ) * a , n * b ) ) ;
    }
    else {
      long count = n % m ;
      long x = m * ( n / m + 1 ) - n ;
      long min = ( long ) Math . min ( count * b , x * a ) ;
      System . out . println ( min ) ;
    }
  }
}

public static void main ( String [ ] args ) { Scanner input = new Scanner ( System . in ) ; long n = input . nextLong ( ) ; long m = input . nextLong ( ) ; int a = input . nextInt ( ) ; int b = input . nextInt ( ) ; if ( n % m == 0 ) { System . out . println ( 0 ) ; } else { if ( n < m ) { System . out . println ( Math . min ( ( m - n ) * a , n * b ) ) ; } else { long count = n % m ; long x = m * ( n / m + 1 ) - n ; long min = ( long ) Math . min ( count * b , x * a ) ; System . out . println ( min ) ; } } }
(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 (decimal_integer_literal))))) alternative: (block (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 (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) right: (identifier)) (binary_expression left: (identifier) right: (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: (binary_expression left: (identifier) right: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (identifier)) right: (decimal_integer_literal)))) right: (identifier)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (cast_expression type: (integral_type) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (identifier)) (binary_expression left: (identifier) right: (identifier))))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier))))))))))