public static void main ( String [ ] args ) throws IOException {
  String text = input . readLine ( ) ;
  int len = 1 ;
  for ( int i = 1 ;
  i < text . length ( ) ;
  i ++ ) if ( text . charAt ( i ) != text . charAt ( i - 1 ) ) len ++ ;
  if ( len % 2 == 0 ) {
    System . out . println ( 0 ) ;
    return ;
  }
  String [ ] tokens = new String [ len ] ;
  int current = 0 ;
  int last = 0 ;
  for ( int i = 1 ;
  i < text . length ( ) ;
  i ++ ) if ( text . charAt ( i ) != text . charAt ( i - 1 ) ) {
    tokens [ current ] = text . substring ( last , i ) ;
    last = i ;
    current ++ ;
  }
  tokens [ current ] = text . substring ( last ) ;
  for ( int i = 0 ;
  i < tokens . length / 2 ;
  i ++ ) if ( tokens [ i ] . charAt ( 0 ) != tokens [ len - i - 1 ] . charAt ( 0 ) || tokens [ i ] . length ( ) + tokens [ len - i - 1 ] . length ( ) <= 2 ) {
    System . out . println ( 0 ) ;
    return ;
  }
  if ( tokens [ len / 2 ] . length ( ) <= 1 ) {
    System . out . println ( 0 ) ;
    return ;
  }
  System . out . println ( tokens [ len / 2 ] . length ( ) + 1 ) ;
}

public static void main ( String [ ] args ) throws IOException { String text = input . readLine ( ) ; int len = 1 ; for ( int i = 1 ; i < text . length ( ) ; i ++ ) if ( text . charAt ( i ) != text . charAt ( i - 1 ) ) len ++ ; if ( len % 2 == 0 ) { System . out . println ( 0 ) ; return ; } String [ ] tokens = new String [ len ] ; int current = 0 ; int last = 0 ; for ( int i = 1 ; i < text . length ( ) ; i ++ ) if ( text . charAt ( i ) != text . charAt ( i - 1 ) ) { tokens [ current ] = text . substring ( last , i ) ; last = i ; current ++ ; } tokens [ current ] = text . substring ( last ) ; for ( int i = 0 ; i < tokens . length / 2 ; i ++ ) if ( tokens [ i ] . charAt ( 0 ) != tokens [ len - i - 1 ] . charAt ( 0 ) || tokens [ i ] . length ( ) + tokens [ len - i - 1 ] . length ( ) <= 2 ) { System . out . println ( 0 ) ; return ; } if ( tokens [ len / 2 ] . length ( ) <= 1 ) { System . out . println ( 0 ) ; return ; } System . out . println ( tokens [ len / 2 ] . length ( ) + 1 ) ; }
(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: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) update: (update_expression (identifier)) body: (if_statement condition: (parenthesized_expression (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (decimal_integer_literal)))))) consequence: (expression_statement (update_expression (identifier))))) (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: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (decimal_integer_literal)))) (return_statement))) (local_variable_declaration type: (array_type element: (type_identifier) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (array_creation_expression type: (type_identifier) dimensions: (dimensions_expr (identifier))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) update: (update_expression (identifier)) body: (if_statement condition: (parenthesized_expression (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (decimal_integer_literal)))))) consequence: (block (expression_statement (assignment_expression left: (array_access array: (identifier) index: (identifier)) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier) (identifier))))) (expression_statement (assignment_expression left: (identifier) right: (identifier))) (expression_statement (update_expression (identifier)))))) (expression_statement (assignment_expression left: (array_access array: (identifier) index: (identifier)) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (binary_expression left: (field_access object: (identifier) field: (identifier)) right: (decimal_integer_literal))) update: (update_expression (identifier)) body: (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (method_invocation object: (array_access array: (identifier) index: (identifier)) name: (identifier) arguments: (argument_list (decimal_integer_literal))) right: (method_invocation object: (array_access array: (identifier) index: (binary_expression left: (binary_expression left: (identifier) right: (identifier)) right: (decimal_integer_literal))) name: (identifier) arguments: (argument_list (decimal_integer_literal)))) right: (binary_expression left: (binary_expression left: (method_invocation object: (array_access array: (identifier) index: (identifier)) name: (identifier) arguments: (argument_list)) right: (method_invocation object: (array_access array: (identifier) index: (binary_expression left: (binary_expression left: (identifier) right: (identifier)) right: (decimal_integer_literal))) name: (identifier) arguments: (argument_list))) right: (decimal_integer_literal)))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (decimal_integer_literal)))) (return_statement)))) (if_statement condition: (parenthesized_expression (binary_expression left: (method_invocation object: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (decimal_integer_literal))) name: (identifier) arguments: (argument_list)) right: (decimal_integer_literal))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (decimal_integer_literal)))) (return_statement))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (method_invocation object: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (decimal_integer_literal))) name: (identifier) arguments: (argument_list)) right: (decimal_integer_literal)))))))