public static void main ( String [ ] args ) throws IOException {
  Scanner read = new Scanner ( System . in ) ;
  long ans = 0 ;
  int n = read . nextInt ( ) ;
  long [ ] arr = new long [ n + 1 ] ;
  long [ ] pref = new long [ n + 1 ] ;
  for ( int i = 1 ;
  i <= n ;
  i ++ ) {
    arr [ i ] = read . nextLong ( ) ;
    pref [ i ] = pref [ i - 1 ] ^ arr [ i ] ;
  }
  for ( int i = 1 ;
  i <= n ;
  i ++ ) {
    for ( int j = i ;
    j <= n ;
    j ++ ) {
      ans = Math . max ( ans , pref [ j ] ^ pref [ i - 1 ] ) ;
    }
  }
  System . out . println ( ans ) ;
}

public static void main ( String [ ] args ) throws IOException { Scanner read = new Scanner ( System . in ) ; long ans = 0 ; int n = read . nextInt ( ) ; long [ ] arr = new long [ n + 1 ] ; long [ ] pref = new long [ n + 1 ] ; for ( int i = 1 ; i <= n ; i ++ ) { arr [ i ] = read . nextLong ( ) ; pref [ i ] = pref [ i - 1 ] ^ arr [ i ] ; } for ( int i = 1 ; i <= n ; i ++ ) { for ( int j = i ; j <= n ; j ++ ) { ans = Math . max ( ans , pref [ j ] ^ pref [ i - 1 ] ) ; } } System . out . println ( ans ) ; }
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