#include <iostream>
#include <algorithm>
#include <vector>
#include <map>
#define ll long long

using namespace std;

int N, X;
vector<int> v;
map<pair<int,int>,bool> memo;

bool solve(int l, int r) {
    if(memo.count(make_pair(l,r)) > 0) return memo[make_pair(l,r)];
    if(l==r){
        return memo[make_pair(l,r)] = false;
    }
    bool canwin = false;
    ll sum = 0;
    for(int i=l; i<r; i++){
        sum += v[i];
        if(sum > X) break;
        if(!solve(i, r)) canwin = true;
    }
    sum = 0;
    for(int i=r; i>l; i--){
        sum += v[i];
        if(sum > X) break;
        if(!solve(l, i)) canwin = true;
    }
    
    return memo[make_pair(l,r)] = canwin;
}

int main(){
    cin >> N >> X;
    for(int i=0; i<N; i++){
        int a;
        cin >> a;
        v.push_back(a);
    }
    
    if(solve(0, N-1)) cout << "A" << endl;
    else cout << "B" << endl;
    
    return 0;
}