import numpy as np
N = int(input())
A = list(map(int, input().split())) 
F = np.fft.fft(A)
# 振幅スペクトルを計算
amplitude = np.abs(F)
F_amplitude = amplitude / N * 2
F_amplitude[0] = F_amplitude[0] / 2
v = 0
hz = 0
for i in range(len(F_amplitude)):
	if v<F_amplitude[i]:
		hz=i
		v=F_amplitude[i]
L = ['C4','D4','E4','F4','G4','A4','B4']
HZ = [260,293,326,347,391,435,489]
V = [0]*7
for i in range(7):
    for k in range(1,7):
        for j in range(3):
            V[i]+=F_amplitude[HZ[i]*k+j]
ans = 0
v = 0
for i in range(7):
    if v<V[i]:
        ans=i
        v=V[i]
print(L[ans])