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

counter = Hash.new(0)
ans = 0

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

  counter[a] += counter[a - 1] + 1
  counter[a] %= MOD
end

puts ans