Technically, 256.
A submask is designed to separate the network id portion of an IP address from the host or client portion. This helps a router determine whether the packet needs to be forwarded to another network.
The submask indicates the division between the network id and the host information in an ipV4 address. The default subnet mask indicates the presence of a class A, B, or C based network (the default) without subnetting.
Well only way to find that out is at your computer, heres how. Hold the windows key and R (or just open the run menu) and type cmd. Now type in ipconfig /all exactly how i typed it, feel free to copy n paste. Scroll around until you find something labeled subnet mask. Follow the dots to the numbers, and those numbers are your subnet mask.