  We are studying the adaptive bitprobe model to store an arbitrary subset S of
size at most five from a universe U of size m and answer the membership queries
of the form "Is x in S?" in two bitprobes. In this paper, we present a data
structure for the aforementioned problem. Our data structure takes O(m^{10/11})
space. This result improves the non-explicit result by Garg and Radhakrishnan
[2015] which takes O(m^{20/21}) space, and the explicit result by Garg [2016]
which takes O(m^{18/19} ) space for the aforementioned set and query sizes.
