def shift(x):
ret = ''
for ch in x:
if ch == 'z':
ret += 'a'
elif ch == ' ':
ret += ' '
else:
ret += chr(ord(ch) + 1)
return ret
n=int(input())
l=int(input())
s = input()
for _ in range(l % 26):
s = shift(s)
print(s)