local mod = 1000000007 local mfl = math.floor local function badd(x, y) return (x + y) % mod end local function bmul(x, y) local x0, y0 = x % 31623, y % 31623 local x1, y1 = mfl(x / 31623), mfl(y / 31623) return (x1 * y1 * 14122 + (x1 * y0 + x0 * y1) * 31623 + x0 * y0) % mod end local function modpow(src, pow) local res = 1 while 0 < pow do if pow % 2 == 1 then res = bmul(res, src) pow = pow - 1 end src = bmul(src, src) pow = mfl(pow / 2) end return res end local function modinv(src) return modpow(src, mod - 2) end local n, m = io.read("*n", "*n") local combs = {m} for i = 2, m do local v = combs[i - 1] v = bmul(v, m + 1 - i) v = bmul(v, modinv(i)) combs[i] = v end if n < m then print(0) else local flag = true local ret = 0 local comb = 1 for i = m, 1, -1 do local v = modpow(i, n) v = bmul(v, combs[i]) if not flag then v = mod - v end ret = badd(ret, v) flag = not flag end print(ret) end