line = readlines
len = line.length
i = 0

while i < len
    line[i] = line[i].chomp
    i += 1
end

N = line[0].to_i
S = line[1]

a = "ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZ"
ar = []
for i in 1..52 do
  ar.push(a[i-1])
end

answer = ""
for i in 1..S.length do
  num = ar.index(S[i-1])
  answer = answer + ar[num+N]
end

print answer