public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  int n = sc . nextInt ( ) ;
  int [ ] b = new int [ n ] ;
  for ( int i = 1 ;
  i < n ;
  i ++ ) {
    b [ i ] = sc . nextInt ( ) ;
  }
  List < List < Integer >> list = new ArrayList < > ( ) ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    List < Integer > subList = new ArrayList < > ( ) ;
    for ( int j = 0 ;
    j < n ;
    j ++ ) {
      if ( i + 1 == b [ j ] ) {
        subList . add ( j ) ;
      }
    }
    list . add ( subList ) ;
  }
  int [ ] p = new int [ n ] ;
  for ( int i = n - 1 ;
  i >= 0 ;
  i -- ) {
    if ( list . get ( i ) . size ( ) == 0 ) {
      p [ i ] = 1 ;
    }
    else {
      int min = ( int ) 1e9 ;
      int max = 0 ;
      for ( int j = 0 ;
      j < list . get ( i ) . size ( ) ;
      j ++ ) {
        min = Math . min ( min , p [ list . get ( i ) . get ( j ) ] ) ;
        max = Math . max ( max , p [ list . get ( i ) . get ( j ) ] ) ;
      }
      p [ i ] = min + max + 1 ;
    }
  }
  System . out . println ( p [ 0 ] ) ;
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; int n = sc . nextInt ( ) ; int [ ] b = new int [ n ] ; for ( int i = 1 ; i < n ; i ++ ) { b [ i ] = sc . nextInt ( ) ; } List < List < Integer > > list = new ArrayList < > ( ) ; for ( int i = 0 ; i < n ; i ++ ) { List < Integer > subList = new ArrayList < > ( ) ; for ( int j = 0 ; j < n ; j ++ ) { if ( i + 1 == b [ j ] ) { subList . add ( j ) ; } } list . add ( subList ) ; } int [ ] p = new int [ n ] ; for ( int i = n - 1 ; i >= 0 ; i -- ) { if ( list . get ( i ) . size ( ) == 0 ) { p [ i ] = 1 ; } else { int min = ( int ) 1e9 ; int max = 0 ; for ( int j = 0 ; j < list . get ( i ) . size ( ) ; j ++ ) { min = Math . min ( min , p [ list . get ( i ) . get ( j ) ] ) ; max = Math . max ( max , p [ list . get ( i ) . get ( j ) ] ) ; } p [ i ] = min + max + 1 ; } } System . out . println ( p [ 0 ] ) ; }
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