On May 1, Ramona and Santonio orally agree that Santonio will guide a party from the base of Mount McKinley to its summit and from the summit to a return to the base. Under the agreement, Ramona will pay for the service after the completion of the climb on June 1. On May 1, is this contract express or implied? On May 31, after the climb has been made but before payment is paid, is the contract executed or executory?