public static void main ( String [ ] args ) {
  FastReader fr = new FastReader ( ) ;
  Scanner sc = new Scanner ( System . in ) ;
  int n = fr . nextInt ( ) ;
  ArrayList < Integer > a = new ArrayList < > ( ) , b = new ArrayList < > ( ) ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    int x = fr . nextInt ( ) ;
    if ( x >= 0 ) a . add ( x ) ;
    else b . add ( x ) ;
  }
  int A = 0 , B = 0 ;
  for ( Integer i : a ) A += i ;
  for ( Integer i : b ) B += i ;
  System . out . println ( A - B ) ;
}

public static void main ( String [ ] args ) { FastReader fr = new FastReader ( ) ; Scanner sc = new Scanner ( System . in ) ; int n = fr . nextInt ( ) ; ArrayList < Integer > a = new ArrayList < > ( ) , b = new ArrayList < > ( ) ; for ( int i = 0 ; i < n ; i ++ ) { int x = fr . nextInt ( ) ; if ( x >= 0 ) a . add ( x ) ; else b . add ( x ) ; } int A = 0 , B = 0 ; for ( Integer i : a ) A += i ; for ( Integer i : b ) B += i ; System . out . println ( A - B ) ; }
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