local bls, brs = bit.lshift, bit.rshift local bxor = bit.bxor local function grayCode(x) return bxor(x, brs(x, 1)) end -- add_func(idx), rm_func(idx), work_func() local function grayWalk(size, add_func, rm_func, work_func) local prv = 0 local total = bls(1, size) - 1 local bpos = {} for i = 1, size do bpos[bls(1, i - 1)] = i end work_func() for i = 1, total do local v = grayCode(i) if prv < v then prv, v = v, v - prv add_func(bpos[v]) else prv, v = v, prv - v rm_func(bpos[v]) end work_func() end end local n, w = io.read("*n", "*n") local a = {} for i = 1, n do a[i] = io.read("*n") end local ret = 0 local box = {} local subbox = {} local subcnt = 0 local subv = 0 local f = false local function subadd(idx) subv = subv - brs(a[subbox[idx]], 1) end local function subrm(idx) subv = subv + brs(a[subbox[idx]], 1) end local function subwork() if w == subv then f = true end end for i = 1, n do box[i] = false end local function add_func(idx) box[idx] = true end local function rm_func(idx) box[idx] = false end local function work_func() subcnt = 0 subv = 0 f = false for i = 1, n do if box[i] then subcnt = subcnt + 1 subbox[subcnt] = i subv = subv + a[i] end end grayWalk(subcnt, subadd, subrm, subwork) if f then ret = ret + 1 end end grayWalk(n, add_func, rm_func, work_func) if w == 0 then ret = ret - 1 end print(ret)