sign

textout = ""
finalout = ""
lettercount = 1
count = 1
alphabet = "#abcdefghijklmopqrstuvwxyz" # blank first character, cause python starts at 0
shift = int(raw_input()) # get the shift
text = "#"+raw_input() # get the text to encrypt, once again, blank first character cause python

textout = "" # where we are going to put the result
for i in range(1, len(text)): # repeat length of text
    lettercount = 1
    true = 0
    while (lettercount < len(alphabet) and true == 0):
        if text[count] == alphabet[lettercount]:
            # your problem is here, below. something wrong with the shift logic
            textout += alphabet[((lettercount + shift) % len(alphabet)) ]
            true = 1
        lettercount += 1
    count += 1

    # what does this do anyways?
    #if (true == 0):
    #    textout += text[count]

# show the result
print textout