local mod = 1000000007 local mfl = math.floor local function bmul(x, y) local x1, y1 = x % 10000, y % 10000 local x2, y2 = mfl(x / 10000) % 10000, mfl(y / 10000) % 10000 local x3, y3 = mfl(x / 100000000), mfl(y / 100000000) local ret = (x1 * y1 + (x1 * y2 + x2 * y1) * 10000) % mod ret = (ret + (x1 * y3 + x2 * y2 + x3 * y1) * 10000 % mod * 10000 % mod) % mod ret = (ret + (x2 * y3 + x3 * y2) * 10000 % mod * 10000 % mod * 10000) % mod ret = (ret + x3 * y3 * 930000007) % mod return ret 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 = io.read("*n") local numer = 1 for i = 2, 2 * n do numer = (numer * i) % mod end local denom = modpow(2, n) print(bmul(numer, modinv(denom)))