#include "bits/stdc++.h"

using namespace std;

using i64 = long long;


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

    vector<i64> r(n + 1, 0);
    for(i = 0; i < n; ++i)
        r[i + 1] = r[i] + v[i];

    array<int, 5000> nex, prev;
    for(i = 0; i < n; ++i){
        auto it = upper_bound(r.begin(), r.end(), r[i] + x);
        int idx = distance(r.begin(), it);
        nex[i] = min(idx, n);
        auto it2 = lower_bound(r.begin(), r.end(), r[i + 1] - x);
        idx = distance(r.begin(), it2);
        prev[i] = max(0, idx - 1);
    }

    bitset<25000000> a;

    for(k = 1; k < n; ++k)
        for(i = 0, j = k; j < n; ++i, ++j){
            bool f = false;
            for(right = max(i, prev[j]); right < j; ++right)
                if(!a[i * 5000 + right]){
                    f = true;
                    break;
                }
            int left_bound = min(nex[i], j + 1);
            if(!f)
                for(left = i + 1; left < left_bound; ++left)
                    if(!a[left * 5000 + j]){
                        f = true;
                        break;
                    }

            a.set(i * 5000 + j, f);
        }

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