n = int(input())
a = list(map(int,input().split()))
import random
ll = []
for _ in range(2000):
    shikii = round(max(a) * random.uniform(0.7, 0.9))

    peek = [-10 ** 9]
    for i in range(100, n - 100):
        if a[i] >= shikii and abs(peek[-1] - i) >= 89:
            peek.append(i)

    peek = peek[1:]
    l = len(peek)
    if l <= 5: continue
    f = []
    for i in range(l - 1):
        f.append(n / (peek[i + 1] - peek[i]))
    f.sort()
    f = f[round(3 * l / 4)]

    sa = 10 ** 9
    ans = None
    li = [(261.6, 'C4'), (294.3, 'D4'), (327.0, 'E4'), (348.8, 'F4'), (392.4, 'G4'), (436.0, 'A4'), (490.5, 'B4')]

    for v, c in li:
        if abs(f - v) < sa:
            sa = abs(f - v)
            ans = c
    ll.append(ans)
from collections import Counter

ll = Counter(ll)
print(ll.most_common()[0][0])