Can I travel with a 144h visa?

Spanish national here. I want to fly from Ulaanbataar to Shanghai and apply for a 144h free transit. Then stay a couple days in Shanghai, travel to Beijing, stay a couple more days there and fly back to Europe (less than 144h of course). Is that ok, getting the free transit in Shangai, then travelling to another city (Beijing) and flying out of the country from there?