#include "bits/stdc++.h"

using namespace std;

using i64 = long long;


signed main(){
    int n, x;
    cin >> n >> x;
    vector<int> v(n);
    for(auto& w : v)
        cin >> w;

    vector<vector<int>> a(n, vector<int>(n, 0));

    for(int i = 0; i < n; ++i)
        for(int len = 0; len < n; ++len){
            int j = i + len;
            if(j >= n)
                break;
            bool f = false;
            int right_sum = v[j];
            for(int right = j - 1; right >= i; --right){
                if(!a[i][right]){
                    f = true;
                    break;
                }
                right_sum += v[right];
                if(right_sum > x)
                    break;
            }
            if(!f){
                int left_sum = v[i];
                for(int left = i + 1; left <= j; ++left){
                    if(!a[left][j]){
                        f = true;
                        break;
                    }
                    left_sum += v[left];
                    if(left_sum > x)
                        break;
                }
            }

            a[i][j] = f;
        }

    cout << (a[0][n - 1] ? "A" : "B") << endl;
}