import numpy as np

freqs = [262, 294, 327, 349, 392, 436, 491]
names = ['C4', 'D4', 'E4', 'F4', 'G4', 'A4', 'B4']

N = int(input())
A = list(map(float, input().split()))

Afft = np.abs(np.fft.rfft(A * np.hanning(N)))[1:]

print(names[np.argmax(Afft[freqs])])