local cos = math.cos
local sin = math.sin
local pi2 = 2 * math.pi
local n = io.read("*n")
local t = {}
for i = 1, n do
  t[i] = io.read("*n") / 32768
end
local a = {261.6, 294.3, 327.0, 348.8, 392.4, 436.0, 490.5}
local b = {"C4", "D4", "E4", "F4", "G4", "A4", "B4"}
local c = {}
local pos, val = 0, 0
for i = 1, 7 do
  local x, y = 0, 0
  for j = 1, n do
    x = x + sin(j * pi2 / 44100 * a[i]) * t[j]
    y = y + cos(j * pi2 / 44100 * a[i]) * t[j]
  end
  local z = x * x + y * y
  if i == 1 or val < z then
    pos, val = i, z
  end
end
print(b[pos])