public static void main ( String [ ] args ) {
  Scanner scan = new Scanner ( System . in ) ;
  int N = scan . nextInt ( ) ;
  long [ ] sum = new long [ N ] ;
  long [ ] a = new long [ N ] ;
  long [ ] abssum = new long [ N + 1 ] ;
  List < Integer > minusIndex = new ArrayList < > ( ) ;
  for ( int i = 0 ;
  i < N ;
  ++ i ) {
    if ( i == 0 ) {
      a [ i ] = scan . nextLong ( ) ;
      sum [ i ] = a [ i ] ;
    }
    else {
      boolean minus = ( scan . next ( ) . equals ( "-" ) ) ;
      a [ i ] = scan . nextLong ( ) ;
      sum [ i ] = sum [ i - 1 ] + a [ i ] * ( minus ? - 1 : 1 ) ;
      if ( minus ) minusIndex . add ( i - 1 ) ;
    }
  }
  for ( int i = N - 1 ;
  i >= 0 ;
  -- i ) abssum [ i ] = abssum [ i + 1 ] + a [ i ] ;
  long ans = sum [ N - 1 ] ;
  for ( int i = 0 ;
  i < minusIndex . size ( ) - 1 ;
  ++ i ) {
    ans = Math . max ( ans , sum [ minusIndex . get ( i ) ] - abssum [ minusIndex . get ( i ) + 1 ] + 2 * abssum [ minusIndex . get ( i + 1 ) + 1 ] ) ;
  }
  System . out . println ( ans ) ;
}

public static void main ( String [ ] args ) { Scanner scan = new Scanner ( System . in ) ; int N = scan . nextInt ( ) ; long [ ] sum = new long [ N ] ; long [ ] a = new long [ N ] ; long [ ] abssum = new long [ N + 1 ] ; List < Integer > minusIndex = new ArrayList < > ( ) ; for ( int i = 0 ; i < N ; ++ i ) { if ( i == 0 ) { a [ i ] = scan . nextLong ( ) ; sum [ i ] = a [ i ] ; } else { boolean minus = ( scan . next ( ) . equals ( " - " ) ) ; a [ i ] = scan . nextLong ( ) ; sum [ i ] = sum [ i - 1 ] + a [ i ] * ( minus ? - 1 : 1 ) ; if ( minus ) minusIndex . add ( i - 1 ) ; } } for ( int i = N - 1 ; i >= 0 ; -- i ) abssum [ i ] = abssum [ i + 1 ] + a [ i ] ; long ans = sum [ N - 1 ] ; for ( int i = 0 ; i < minusIndex . size ( ) - 1 ; ++ i ) { ans = Math . max ( ans , sum [ minusIndex . get ( i ) ] - abssum [ minusIndex . get ( i ) + 1 ] + 2 * abssum [ minusIndex . get ( i + 1 ) + 1 ] ) ; } System . out . println ( ans ) ; }
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