public static void main ( String args [ ] ) {
  PrintWriter out = new PrintWriter ( System . out ) ;
  FastScanner fs = new FastScanner ( ) ;
  int t = fs . nextInt ( ) ;
  for ( int test_case = 1 ;
  test_case <= t ;
  test_case ++ ) {
    int n = fs . nextInt ( ) , k = fs . nextInt ( ) ;
    if ( n < k ) {
      System . out . println ( k - n ) ;
    }
    else {
      if ( k % 2 == 0 && n % 2 == 0 ) {
        System . out . println ( 0 ) ;
      }
      else if ( k % 2 == 1 && n % 2 == 1 ) {
        System . out . println ( 0 ) ;
      }
      else {
        System . out . println ( 1 ) ;
      }
    }
  }
  out . close ( ) ;
}

public static void main ( String args [ ] ) { PrintWriter out = new PrintWriter ( System . out ) ; FastScanner fs = new FastScanner ( ) ; int t = fs . nextInt ( ) ; for ( int test_case = 1 ; test_case <= t ; test_case ++ ) { int n = fs . nextInt ( ) , k = fs . nextInt ( ) ; if ( n < k ) { System . out . println ( k - n ) ; } else { if ( k % 2 == 0 && n % 2 == 0 ) { System . out . println ( 0 ) ; } else if ( k % 2 == 1 && n % 2 == 1 ) { System . out . println ( 0 ) ; } else { System . out . println ( 1 ) ; } } } out . close ( ) ; }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (type_identifier) name: (identifier) dimensions: (dimensions))) 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)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (identifier)))))) alternative: (block (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (decimal_integer_literal)) right: (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))))) alternative: (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (decimal_integer_literal)) right: (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))))) alternative: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (decimal_integer_literal))))))))))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))))