print((function (f, a, b)
	local r,t = f(a,0,0)
	r,t = f(b,r,t)
	return t>0 and t>r and t or r
end)(function (s, r, t)
	for i=1,#s do if s:sub(i,i)=="x" then r,t = t>r and t or r,0 else t = t+1 end end
	return r,t
end, io.stdin:read("*l"), io.stdin:read("*l")))