#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
constexpr int INF = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr double EPS = 1e-8;
constexpr int MOD = 1000000007;
// constexpr int MOD = 998244353;
constexpr int DY4[]{1, 0, -1, 0}, DX4[]{0, -1, 0, 1};
constexpr int DY8[]{1, 1, 0, -1, -1, -1, 0, 1};
constexpr int DX8[]{0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U>
inline bool chmax(T& a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U>
inline bool chmin(T& a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    std::cin.tie(nullptr);
    std::ios_base::sync_with_stdio(false);
    std::cout << fixed << setprecision(20);
  }
} iosetup;

int main() {
  constexpr int N = 7;
  const vector<string> SCALE{"C4", "D4", "E4", "F4", "G4", "A4", "B4"};
  const vector<double> hz{261.6, 294.3, 327.0, 348.8, 392.4, 436.0, 490.5};

  int n; cin >> n;
  vector<int> a(n); REP(i, n) cin >> a[i];
  const int h = max_element(ALL(a)) - a.begin();
  int ans = -1, mx = -INF;
  REP(i, N) {
    const int d = round(n / hz[i]);
    if (chmax(mx, a[h + d < n ? h + d : h - d])) ans = i;
  }
  cout << SCALE[ans] << '\n';
  return 0;
}