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 = [261.6,294.3,327.0,348.8,392.4,436.0,490.5]
ans = 0
v = 1000
for i in range(7):
    if v>min(hz/HZ[i]-int(hz/HZ[i]),abs(1-hz/HZ[i]+int(hz/HZ[i])))*HZ[i]/HZ[0]:
        v = min(hz/HZ[i]-int(hz/HZ[i]),abs(1-hz/HZ[i]+int(hz/HZ[i])))*HZ[i]/HZ[0]
        ans=i
print(L[ans])