N = gets.to_i
A = gets.split.map { _1.to_i }
M = 998244353
C = Hash.new(0)
A.each do |a|
  C[a] = (C[a] + (a.zero? ? 0 : C[a - 1]) + 1) % M
end
((C.values.sum - N) % M).tap { puts(_1) }
# ref: https://yukicoder.me/submissions/791136