h='abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz'
l=[]
a=int(input())
b=input()
for i in b:
     l.append(h[h.find(i,0)+a])
print(''.join(l))