public static void main ( String args [ ] ) throws IOException {
  String str = sc . next ( ) ;
  if ( ! str . contains ( "Danil" ) && ! str . contains ( "Olya" ) && ! str . contains ( "Slava" ) && ! str . contains ( "Ann" ) && ! str . contains ( "Nikita" ) ) System . out . println ( "No" ) ;
  else {
    HashSet < String > hs = new HashSet < String > ( ) ;
    hs . add ( "Danil" ) ;
    hs . add ( "Olya" ) ;
    hs . add ( "Slava" ) ;
    hs . add ( "Ann" ) ;
    hs . add ( "Nikita" ) ;
    boolean flag = true ;
    int count = 0 ;
    for ( String i : hs ) {
      int index = 0 ;
      while ( true ) {
        index = str . indexOf ( i , index ) ;
        if ( index != - 1 ) {
          count ++ ;
          if ( count == 2 ) {
            System . out . println ( "No" ) ;
            flag = false ;
            break ;
          }
          index += i . length ( ) ;
        }
        else {
          break ;
        }
      }
      if ( ! flag ) break ;
    }
    if ( flag ) System . out . println ( "Yes" ) ;
  }
}

public static void main ( String args [ ] ) throws IOException { String str = sc . next ( ) ; if ( ! str . contains ( " Danil " ) && ! str . contains ( " Olya " ) && ! str . contains ( " Slava " ) && ! str . contains ( " Ann " ) && ! str . contains ( " Nikita " ) ) System . out . println ( " No " ) ; else { HashSet < String > hs = new HashSet < String > ( ) ; hs . add ( " Danil " ) ; hs . add ( " Olya " ) ; hs . add ( " Slava " ) ; hs . add ( " Ann " ) ; hs . add ( " Nikita " ) ; boolean flag = true ; int count = 0 ; for ( String i : hs ) { int index = 0 ; while ( true ) { index = str . indexOf ( i , index ) ; if ( index != - 1 ) { count ++ ; if ( count == 2 ) { System . out . println ( " No " ) ; flag = false ; break ; } index += i . length ( ) ; } else { break ; } } if ( ! flag ) break ; } if ( flag ) System . out . println ( " Yes " ) ; } }
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