I've seen the standover height posted for a few sizes of IP-057 but I've not see any for an IP-256, they might be similar. If they are roughly the same, the standover I've seen for a medium IP-057 frame is 805mm (31.7"). However, that measurement is taken at the midpoint of the top tube, not exactly where you would be standing so it's probably less than that height.
I just went out and measured the standover height of my Large IP-057 and found it to be 31.7" up to the top tube where the rider would stand.
For my Large IP-036 Full Suspension 29er, the standover measured 31".
Hopefully someone with a small or medium IP-256 can post a measurement for you.