array = Array.new

while val = gets do
    array.push(val.chomp)
end

n = array[0].to_i
s = array[1]

alphabets = ('A'..'Z').to_a
strings = ''

if n > 0
    for i in 1..s.length do
        char = s.slice(i-1)
        index = alphabets.index(char)
        strings += alphabets[(index + n) % 26]
    end
else
    strings = s
end

puts(strings)