local mod = 998244353
local mfl = math.floor
local function bmul(x, y)
  local x0, y0 = x % 31596, y % 31596
  local x1, y1 = mfl(x / 31596), mfl(y / 31596)
  return (x1 * y1 * 62863 + (x1 * y0 + x0 * y1) * 31596 + x0 * y0) % mod
end
local function badd(x, y)
  return (x + y) % mod
end

local n = io.read("*n")
local a, b, c = {}, {}, {}
local lim = 1002
for i = 1, lim do
  a[i], b[i], c[i] = 0, 0, 0
end
local nothing = 1
for i = 1, n do
  for j = lim, 1, -1 do
    c[j] = badd(c[j] * 25, b[j])
    b[j] = badd(b[j] * 25, a[j])
    if 1 < j then
      a[j] = badd(a[j] * 25, c[j - 1])
    else
      a[j] = badd(a[j] * 25, nothing)
    end
  end
  nothing = bmul(nothing, 25)
end
local ret = 0
for i = 1, lim do
  local x = badd(a[i], b[i])
  x = bmul(x, i - 1)
  local y = bmul(c[i], i)
  ret = badd(ret, x)
  ret = badd(ret, y)
end
print(ret)