#include<iostream>

using namespace std;

int main() {
    int s, n, a;
    cin >> s >> n;
    int cnt = 1;
    for (int i = 1; i <= n; i++) {
        cin >> a;
        if (a > s)cnt++;
    }
    if (cnt <= n * 0.1)cout << "A";
    else if (cnt <= n * 0.3)cout << "B";
    else if (cnt <= n * 0.6)cout << "C";
    else if (cnt <= n * 0.8)cout << "D";
    else cout << "E";
    return 0;
}