public static void main ( String [ ] args ) {
  Scanner in = new Scanner ( System . in ) ;
  int n = in . nextInt ( ) ;
  long t = in . nextLong ( ) ;
  String num = in . next ( ) ;
  int dec = num . indexOf ( "." ) ;
  num = num . replace ( "." , "" ) ;
  char [ ] cs = num . toCharArray ( ) ;
  int len = cs . length ;
  for ( int i = dec ;
  i < len ;
  i ++ ) {
    if ( cs [ i ] - '0' >= 5 ) {
      len = i + 1 ;
      break ;
    }
  }
  while ( t > 0 ) {
    int roundIdx = - 1 ;
    for ( int i = len - 1 ;
    i >= dec ;
    i -- ) {
      int v = cs [ i ] - '0' ;
      if ( v >= 5 ) {
        roundIdx = i ;
        break ;
      }
    }
    if ( roundIdx == - 1 ) break ;
    len = roundIdx ;
    while ( len > 0 && cs [ len - 1 ] == '9' ) {
      cs [ len - 1 ] = '0' ;
      len -- ;
    }
    if ( len == 0 ) {
      System . out . print ( "1" ) ;
      break ;
    }
    cs [ len - 1 ] ++ ;
    t -- ;
  }
  System . out . print ( new String ( cs , 0 , dec ) ) ;
  if ( len - dec > 0 ) {
    System . out . print ( "." ) ;
    System . out . println ( new String ( cs , dec , len - dec ) ) ;
  }
  else {
    System . out . println ( ) ;
  }
}

public static void main ( String [ ] args ) { Scanner in = new Scanner ( System . in ) ; int n = in . nextInt ( ) ; long t = in . nextLong ( ) ; String num = in . next ( ) ; int dec = num . indexOf ( " . " ) ; num = num . replace ( " . " , " " ) ; char [ ] cs = num . toCharArray ( ) ; int len = cs . length ; for ( int i = dec ; i < len ; i ++ ) { if ( cs [ i ] - '0' >= 5 ) { len = i + 1 ; break ; } } while ( t > 0 ) { int roundIdx = - 1 ; for ( int i = len - 1 ; i >= dec ; i -- ) { int v = cs [ i ] - '0' ; if ( v >= 5 ) { roundIdx = i ; break ; } } if ( roundIdx == - 1 ) break ; len = roundIdx ; while ( len > 0 && cs [ len - 1 ] == '9' ) { cs [ len - 1 ] = '0' ; len -- ; } if ( len == 0 ) { System . out . print ( "1" ) ; break ; } cs [ len - 1 ] ++ ; t -- ; } System . out . print ( new String ( cs , 0 , dec ) ) ; if ( len - dec > 0 ) { System . out . print ( " . " ) ; System . out . println ( new String ( cs , dec , len - dec ) ) ; } else { System . out . println ( ) ; } }
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object: (identifier) name: (identifier) arguments: (argument_list)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (string_literal))))) (expression_statement (assignment_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (string_literal) (string_literal))))) (local_variable_declaration type: (array_type element: (integral_type) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (field_access object: (identifier) field: (identifier)))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: 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(binary_expression left: (identifier) right: (identifier)))))))) alternative: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list)))))))