convert = {x:"" for x in range(26)}

for i in range(26):
    convert[i] = chr(ord("A") + i)

n = int(input())
d = list(map(int, input().split()))
d.sort()

C = [0 for _ in range(n)]

for i in range(n):
    C[i] = d[i] % 26

ans = ""
for c in C:
    ans += convert[c]

print(ans)