import sys
input = sys.stdin.readline
def iinput(): return int(input())
def sinput(): return input().rstrip()
def i0input(): return int(input()) - 1
def linput(): return list(input().split())
def liinput(): return list(map(int, input().split()))
def miinput(): return map(int, input().split())
def li0input(): return list(map(lambda x: int(x) - 1, input().split()))
def mi0input(): return map(lambda x: int(x) - 1, input().split())
INF = 10**20
MOD = 1000000007

import numpy as np

N = iinput()
A = liinput()

X = np.fft.fft(A)

X = list(map(abs, X))
res = 0
for i, x in enumerate(X[:500]):
    if x > res:
        res = x
        ans = i

K = [261.6, 294.3, 327.0, 348.8, 392.4, 436.0, 490.5]
KK = ['C4', 'D4', 'E4', 'F4', 'G4', 'A4', 'B4']

res = INF
for i in range(7):
    if abs(ans-K[i]) < res:
        res = abs(ans-K[i])
        a = i

print(KK[a])