N = gets.to_i
A = gets.split.map(&:to_i)
MOD = 998_244_353

counter = Hash.new { |h, k| h[k] = Hash.new(0) }
ans = 0

A.each do |a|
  counter[a - 1].each do |len, cnt|
    ans += cnt
    ans %= MOD
  end

  counter[a - 1].each do |len, cnt|
    counter[a][len + 1] += cnt
  end
  counter[a][1] += 1
end

puts ans