public static void main ( String [ ] args ) {
  Scanner input = new Scanner ( System . in ) ;
  int n = input . nextInt ( ) ;
  int m = input . nextInt ( ) ;
  int [ ] arr = new int [ n ] ;
  for ( int i = 0 ;
  i < m ;
  i ++ ) {
    int from = input . nextInt ( ) - 1 ;
    int to = input . nextInt ( ) - 1 ;
    int value = input . nextInt ( ) ;
    arr [ from ] += value ;
    arr [ to ] -= value ;
  }
  Arrays . sort ( arr ) ;
  int total = 0 ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    if ( arr [ i ] > 0 ) break ;
    total += arr [ i ] ;
  }
  System . out . println ( Math . abs ( total ) ) ;
}

public static void main ( String [ ] args ) { Scanner input = new Scanner ( System . in ) ; int n = input . nextInt ( ) ; int m = input . nextInt ( ) ; int [ ] arr = new int [ n ] ; for ( int i = 0 ; i < m ; i ++ ) { int from = input . nextInt ( ) - 1 ; int to = input . nextInt ( ) - 1 ; int value = input . nextInt ( ) ; arr [ from ] += value ; arr [ to ] -= value ; } Arrays . sort ( arr ) ; int total = 0 ; for ( int i = 0 ; i < n ; i ++ ) { if ( arr [ i ] > 0 ) break ; total += arr [ i ] ; } System . out . println ( Math . abs ( total ) ) ; }
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