public static void main ( String [ ] args ) {
  Scanner s = new Scanner ( System . in ) ;
  int n = s . nextInt ( ) ;
  int d = s . nextInt ( ) ;
  int a [ ] = new int [ n ] ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) a [ i ] = s . nextInt ( ) ;
  Set < Integer > h = new HashSet < > ( ) ;
  h . add ( a [ 0 ] - d ) ;
  h . add ( a [ n - 1 ] + d ) ;
  int k = 1 ;
  for ( int j = 0 ;
  j < n ;
  j ++ ) {
    int a1 = a [ j ] - d ;
    if ( j > 0 && Math . abs ( a1 - a [ j - 1 ] ) >= d ) {
      h . add ( a1 ) ;
    }
    int a2 = a [ j ] + d ;
    if ( j < n - 1 && Math . abs ( a [ j + 1 ] - a2 ) >= d ) {
      h . add ( a2 ) ;
    }
  }
  System . out . println ( h . size ( ) ) ;
}

public static void main ( String [ ] args ) { Scanner s = new Scanner ( System . in ) ; int n = s . nextInt ( ) ; int d = s . nextInt ( ) ; int a [ ] = new int [ n ] ; for ( int i = 0 ; i < n ; i ++ ) a [ i ] = s . nextInt ( ) ; Set < Integer > h = new HashSet < > ( ) ; h . add ( a [ 0 ] - d ) ; h . add ( a [ n - 1 ] + d ) ; int k = 1 ; for ( int j = 0 ; j < n ; j ++ ) { int a1 = a [ j ] - d ; if ( j > 0 && Math . abs ( a1 - a [ j - 1 ] ) >= d ) { h . add ( a1 ) ; } int a2 = a [ j ] + d ; if ( j < n - 1 && Math . abs ( a [ j + 1 ] - a2 ) >= d ) { h . add ( a2 ) ; } } System . out . println ( h . size ( ) ) ; }
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