public static void main ( String [ ] args ) throws IOException {
  BufferedReader reader = new BufferedReader ( new InputStreamReader ( System . in ) ) ;
  int n = Integer . parseInt ( reader . readLine ( ) ) ;
  int [ ] arr = new int [ 1000001 ] ;
  StringTokenizer sToken = new StringTokenizer ( reader . readLine ( ) ) ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    arr [ Integer . parseInt ( sToken . nextToken ( ) ) ] ++ ;
  }
  int rest = 0 ;
  int res = 0 ;
  for ( int i = 0 ;
  i <= 1000000 ;
  i ++ ) {
    res += ( ( rest + arr [ i ] ) % 2 ) ;
    rest = ( rest + arr [ i ] ) / 2 ;
  }
  for ( int i = 0 ;
  i < 40 ;
  i ++ ) {
    res += ( rest % 2 ) ;
    rest = rest / 2 ;
  }
  System . out . println ( res ) ;
}

public static void main ( String [ ] args ) throws IOException { BufferedReader reader = new BufferedReader ( new InputStreamReader ( System . in ) ) ; int n = Integer . parseInt ( reader . readLine ( ) ) ; int [ ] arr = new int [ 1000001 ] ; StringTokenizer sToken = new StringTokenizer ( reader . readLine ( ) ) ; for ( int i = 0 ; i < n ; i ++ ) { arr [ Integer . parseInt ( sToken . nextToken ( ) ) ] ++ ; } int rest = 0 ; int res = 0 ; for ( int i = 0 ; i <= 1000000 ; i ++ ) { res += ( ( rest + arr [ i ] ) % 2 ) ; rest = ( rest + arr [ i ] ) / 2 ; } for ( int i = 0 ; i < 40 ; i ++ ) { res += ( rest % 2 ) ; rest = rest / 2 ; } System . out . println ( res ) ; }
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