N = gets.to_i
S = gets.chomp.chars
arr = ("A".."Z").to_a
res_arr = []
arr.each_with_index do |v, i|
  S.each_with_index do |w, j|
    if v === w
      (i + N) > (arr.count - 1) ? res_arr << arr[i + N - arr.count] : res_arr << arr[i + N]
    end
  end
end
puts res_arr.join