public static void main ( String [ ] args ) {
  Scanner in = new Scanner ( System . in ) ;
  while ( in . hasNext ( ) ) {
    int t = in . nextInt ( ) ;
    for ( int i = 1 ;
    i <= t ;
    i ++ ) {
      int a = in . nextInt ( ) ;
      int b = in . nextInt ( ) ;
      if ( b < a * 2 ) {
        System . out . println ( "-1" + " " + "-1" ) ;
      }
      else {
        System . out . println ( a + " " + 2 * a ) ;
      }
    }
  }
}

public static void main ( String [ ] args ) { Scanner in = new Scanner ( System . in ) ; while ( in . hasNext ( ) ) { int t = in . nextInt ( ) ; for ( int i = 1 ; i <= t ; i ++ ) { int a = in . nextInt ( ) ; int b = in . nextInt ( ) ; if ( b < a * 2 ) { System . out . println ( " - 1" + " ▁ " + " - 1" ) ; } else { System . out . println ( a + " ▁ " + 2 * a ) ; } } } }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (array_type element: (type_identifier) dimensions: (dimensions)) name: (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)))))) (while_statement condition: (parenthesized_expression (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) body: (block (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)))) (local_variable_declaration type: (integral_type) 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: (binary_expression left: (identifier) right: (decimal_integer_literal)))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (binary_expression left: (string_literal) right: (string_literal)) right: (string_literal)))))) alternative: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (binary_expression left: (identifier) right: (string_literal)) right: (binary_expression left: (decimal_integer_literal) right: (identifier))))))))))))))