public static void main ( String [ ] args ) {
  int n , i ;
  int a1 , a2 ;
  int [ ] jerh = new int [ 51 ] ;
  int [ ] jera = new int [ 51 ] ;
  Scanner sc = new Scanner ( System . in ) ;
  n = sc . nextInt ( ) ;
  for ( i = 0 ;
  i < n ;
  i ++ ) {
    a1 = sc . nextInt ( ) ;
    a2 = sc . nextInt ( ) ;
    jerh [ i ] = a1 ;
    jera [ i ] = a2 ;
  }
  int j , sig = 0 ;
  for ( i = 0 ;
  i < n ;
  i ++ ) {
    for ( j = 0 ;
    j < n ;
    j ++ ) {
      if ( jerh [ i ] == jera [ j ] ) sig ++ ;
    }
  }
  System . out . println ( sig ) ;
}

public static void main ( String [ ] args ) { int n , i ; int a1 , a2 ; int [ ] jerh = new int [ 51 ] ; int [ ] jera = new int [ 51 ] ; Scanner sc = new Scanner ( System . in ) ; n = sc . nextInt ( ) ; for ( i = 0 ; i < n ; i ++ ) { a1 = sc . nextInt ( ) ; a2 = sc . nextInt ( ) ; jerh [ i ] = a1 ; jera [ i ] = a2 ; } int j , sig = 0 ; for ( i = 0 ; i < n ; i ++ ) { for ( j = 0 ; j < n ; j ++ ) { if ( jerh [ i ] == jera [ j ] ) sig ++ ; } } System . out . println ( sig ) ; }
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