public static void main ( String [ ] args ) throws Exception {
  Scanner sc = new Scanner ( System . in ) ;
  StringBuilder t = new StringBuilder ( sc . nextLine ( ) ) ;
  int n = t . length ( ) ;
  StringBuilder sb = new StringBuilder ( "" ) ;
  while ( n != 0 ) {
    if ( n % 2 == 0 ) {
      sb . append ( t . charAt ( t . length ( ) - 1 ) ) ;
      t . deleteCharAt ( t . length ( ) - 1 ) ;
    }
    else {
      sb . append ( t . charAt ( 0 ) ) ;
      t . deleteCharAt ( 0 ) ;
    }
    n -- ;
  }
  System . out . println ( sb . reverse ( ) ) ;
}

public static void main ( String [ ] args ) throws Exception { Scanner sc = new Scanner ( System . in ) ; StringBuilder t = new StringBuilder ( sc . nextLine ( ) ) ; int n = t . length ( ) ; StringBuilder sb = new StringBuilder ( " " ) ; while ( n != 0 ) { if ( n % 2 == 0 ) { sb . append ( t . charAt ( t . length ( ) - 1 ) ) ; t . deleteCharAt ( t . length ( ) - 1 ) ; } else { sb . append ( t . charAt ( 0 ) ) ; t . deleteCharAt ( 0 ) ; } n -- ; } System . out . println ( sb . reverse ( ) ) ; }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (array_type element: (type_identifier) dimensions: (dimensions)) name: (identifier))) (throws (type_identifier)) body: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (type_identifier) arguments: (argument_list (field_access object: (identifier) field: (identifier)))))) (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (type_identifier) arguments: (argument_list (method_invocation 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)))) (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (type_identifier) arguments: (argument_list (string_literal))))) (while_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (decimal_integer_literal))) consequence: (block (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) right: (decimal_integer_literal))))))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) right: (decimal_integer_literal)))))) alternative: (block (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (decimal_integer_literal)))))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (decimal_integer_literal)))))) (expression_statement (update_expression (identifier))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))))))