I want to know the answer to the following question:
How many horsemen did Osman I's father bring to aid the Seljuks of Rum?
All the background I'm provided with is that "Ertuğrul, the father of Osman I (founder of the Ottoman Empire), arrived in Anatolia from Merv (Turkmenistan) with 400 horsemen to aid the Seljuks of Rum against the Byzantines.". Is that enough to answer the question?
Answer: yes