public static void main ( String [ ] args ) {
  Scanner input = new Scanner ( System . in ) ;
  int n = input . nextInt ( ) ;
  int t [ ] [ ] = new int [ n + 1 ] [ n + 1 ] ;
  for ( int i = 1 ;
  i <= n ;
  i ++ ) {
    t [ i ] [ 1 ] = 1 ;
  }
  for ( int i = 1 ;
  i <= n ;
  i ++ ) {
    t [ 1 ] [ i ] = 1 ;
  }
  for ( int i = 1 ;
  i <= n ;
  i ++ ) {
    for ( int j = 1 ;
    j <= n ;
    j ++ ) {
      if ( i <= 1 || j <= 1 ) {
        continue ;
      }
      t [ i ] [ j ] = t [ i - 1 ] [ j ] + t [ i ] [ j - 1 ] ;
    }
  }
  int max = 0 ;
  for ( int i = 1 ;
  i <= n ;
  i ++ ) {
    for ( int j = 1 ;
    j <= n ;
    j ++ ) {
      max = Math . max ( max , t [ i ] [ j ] ) ;
    }
  }
  System . out . println ( max ) ;
}

public static void main ( String [ ] args ) { Scanner input = new Scanner ( System . in ) ; int n = input . nextInt ( ) ; int t [ ] [ ] = new int [ n + 1 ] [ n + 1 ] ; for ( int i = 1 ; i <= n ; i ++ ) { t [ i ] [ 1 ] = 1 ; } for ( int i = 1 ; i <= n ; i ++ ) { t [ 1 ] [ i ] = 1 ; } for ( int i = 1 ; i <= n ; i ++ ) { for ( int j = 1 ; j <= n ; j ++ ) { if ( i <= 1 || j <= 1 ) { continue ; } t [ i ] [ j ] = t [ i - 1 ] [ j ] + t [ i ] [ j - 1 ] ; } } int max = 0 ; for ( int i = 1 ; i <= n ; i ++ ) { for ( int j = 1 ; j <= n ; j ++ ) { max = Math . max ( max , t [ i ] [ j ] ) ; } } System . out . println ( max ) ; }
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