local mod = 998244353
local function badd(x, y) return (x + y) % mod end
local n = io.read("*n")
local t = {}
for i = 1, n do
  local a = io.read("*n")
  if t[a - 1] then
    v = badd(t[a - 1], 1)
  else
    v = 1
  end
  if not t[a] then
    t[a] = v
  else
    t[a] = badd(t[a], v)
  end
end
local ret = mod - n
for key, val in pairs(t) do
  ret = badd(ret, val)
end
print(ret)