import math


def getEqCh(n):
    rem24 = (n * 8) % 24
    return int((24 - rem24) % 24 / 8)


def cutStr(str, step):
    res = []
    delta = step
    for i in range(0, len(str), delta):
        res.append(str[i:step])
        step += delta
    return res


s = open('base64.in')
arr = s.readlines()
s.close()
arr[0], arr[1] = int(arr[0]), arr[1][:-1]
n = len(arr[1].split())

newBinArr = (cutStr(''.join([format(int(bin(int(arr[1].split()[i], 16))[2:], 2), '#010b')[2:] for i in range(n)]), 6))
while len(newBinArr[-1]) < 6:
    newBinArr[-1] += '0'

result = ""
alphabet = list("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/")
for item in newBinArr:
    result += alphabet[int(item, 2)]
result += getEqCh(arr[0]) * '='

f = open('base64.out', 'w')
f.write(f"{result}")
f.close()