let read f = stdin.ReadLine() |> f
let n = read int
let s = stdin.ReadLine()
let table = "ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZ".ToCharArray()
for x in s do
    let i = Array.findIndex ((=)x) table
    table.[i+n]
    |> printf "%c"