public static void main ( String [ ] args ) throws IOException {
  BufferedReader inp = new BufferedReader ( new InputStreamReader ( System . in ) ) ;
  BufferedWriter out = new BufferedWriter ( new OutputStreamWriter ( System . out ) ) ;
  int size = Integer . parseInt ( inp . readLine ( ) ) ;
  int [ ] given = new int [ size ] ;
  String [ ] s1 = inp . readLine ( ) . split ( " " ) ;
  String [ ] s2 = inp . readLine ( ) . split ( " " ) ;
  int [ ] given1 = new int [ size ] ;
  for ( int i = 0 ;
  i < size ;
  i ++ ) {
    given1 [ i ] = Integer . parseInt ( s1 [ i ] ) ;
    given [ i ] = Integer . parseInt ( s2 [ i ] ) ;
  }
  int i = 0 ;
  int j = 0 ;
  int count = 0 ;
  while ( i < size && j < size ) {
    if ( given1 [ i ] == given [ j ] ) {
      count ++ ;
      i ++ ;
      j ++ ;
    }
    else {
      j ++ ;
    }
  }
  System . out . println ( size - count ) ;
}

public static void main ( String [ ] args ) throws IOException { BufferedReader inp = new BufferedReader ( new InputStreamReader ( System . in ) ) ; BufferedWriter out = new BufferedWriter ( new OutputStreamWriter ( System . out ) ) ; int size = Integer . parseInt ( inp . readLine ( ) ) ; int [ ] given = new int [ size ] ; String [ ] s1 = inp . readLine ( ) . split ( " ▁ " ) ; String [ ] s2 = inp . readLine ( ) . split ( " ▁ " ) ; int [ ] given1 = new int [ size ] ; for ( int i = 0 ; i < size ; i ++ ) { given1 [ i ] = Integer . parseInt ( s1 [ i ] ) ; given [ i ] = Integer . parseInt ( s2 [ i ] ) ; } int i = 0 ; int j = 0 ; int count = 0 ; while ( i < size && j < size ) { if ( given1 [ i ] == given [ j ] ) { count ++ ; i ++ ; j ++ ; } else { j ++ ; } } System . out . println ( size - count ) ; }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (array_type element: (type_identifier) dimensions: (dimensions)) name: (identifier))) (throws (type_identifier)) body: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (type_identifier) arguments: (argument_list (object_creation_expression type: (type_identifier) arguments: (argument_list (field_access object: (identifier) field: (identifier)))))))) (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (type_identifier) arguments: (argument_list (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 (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: (array_type element: (type_identifier) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) name: (identifier) arguments: (argument_list (string_literal))))) (local_variable_declaration type: (array_type element: (type_identifier) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) name: (identifier) arguments: (argument_list (string_literal))))) (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))))) (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 (array_access array: (identifier) index: (identifier)))))) (expression_statement (assignment_expression left: (array_access array: (identifier) index: (identifier)) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (array_access array: (identifier) index: (identifier)))))))) (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))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (while_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (identifier)) right: (binary_expression left: (identifier) right: (identifier)))) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (array_access array: (identifier) index: (identifier)) right: (array_access array: (identifier) index: (identifier)))) consequence: (block (expression_statement (update_expression (identifier))) (expression_statement (update_expression (identifier))) (expression_statement (update_expression (identifier)))) alternative: (block (expression_statement (update_expression (identifier))))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (identifier)))))))