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?