# -*- coding: utf-8 -*-
import numpy as np

N = int(input())
A = list(map(float, input().split()))
A = np.array(A)
F = np.abs(np.fft.fft(A))

candidate = { 'C4': 261.6, 'D4': 294.3, 'E4': 327.0, 'F4': 348.8, 'G4': 392.4, 'A4': 436.0, 'B4': 490.5  }
max_val = -1
ans = None
for k, f in candidate.items():
    val = F[int(np.round(f * 1.0))]
    if val > max_val:
        max_val = val
        ans = k        
print(ans)