N=int(input())
A=list(map(int,input().split()))
import numpy as np

fs=44100
fft = np.fft.fft(A)

kouho = [261.6, 294.3, 327.0, 348.8, 392.4, 436.0, 490.5]
takasa = ["C4", "D4", "E4", "F4", "G4", "A4", "B4"]
gmax=0
idx=0
for i,k in enumerate(kouho):
    g = abs(fft[round(k)])
    if gmax<g:
        gmax=g
        idx=i
print(takasa[idx])