#include <bits/stdc++.h>
using namespace std;

int main() {
	int score, n;
	cin >> score >> n;
	
	vector<int> scores(n - 1);
	for (int i = 0; i < n - 1; ++i) {
		cin >> scores[i];
	}
	
	scores.push_back(score);
	sort(scores.begin(), scores.end(), greater<int>());
	
	int rank = find(scores.begin(), scores.end(), score) - scores.begin() + 1;
	
	if (rank <= n * 0.1) {
		cout << "A" << endl;
	} else if (rank <= n * 0.3) {
		cout << "B" << endl;
	} else if (rank <= n * 0.6) {
		cout << "C" << endl;
	} else if (rank <= n * 0.8) {
		cout << "D" << endl;
	} else {
		cout << "E" << endl;
	}
	
	return 0;
}