#include<iostream>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<bitset>
#include<stack>
#include<unordered_map>
#include<utility>
#include<cassert>
#include<complex>
using namespace std;

//#define int long long
typedef long long ll;

typedef unsigned long long ul;
typedef unsigned int ui;
const ll mod = 1000000007;
const ll INF = (1e+18) + 7;
typedef pair<int, int>P;
#define stop char nyaa;cin>>nyaa;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
#define all(v) (v).begin(),(v).end()
typedef pair<ll, ll> LP;
typedef long double ld;
typedef pair<ld, ld> LDP;
const ld eps = 1e-6;
const ld pi = acos(-1.0);
//typedef vector<vector<ll>> mat;
typedef vector<int> vec;

ll mod_pow(ll a, ll n) {
	ll res = 1;
	while (n) {
		if (n & 1)res = res * a%mod;
		a = a * a%mod; n >>= 1;
	}
	return res;
}

struct modint {
	ll n;
	modint() :n(0) { ; }
	modint(ll m) :n(m) {
		if (n >= mod)n %= mod;
		else if (n < 0)n = (n%mod + mod) % mod;
	}
	operator int() { return n; }
};
bool operator==(modint a, modint b) { return a.n == b.n; }
modint operator+=(modint &a, modint b) { a.n += b.n; if (a.n >= mod)a.n -= mod; return a; }
modint operator-=(modint &a, modint b) { a.n -= b.n; if (a.n < 0)a.n += mod; return a; }
modint operator*=(modint &a, modint b) { a.n = ((ll)a.n*b.n) % mod; return a; }
modint operator+(modint a, modint b) { return a += b; }
modint operator-(modint a, modint b) { return a -= b; }
modint operator*(modint a, modint b) { return a *= b; }
modint operator^(modint a, int n) {
	if (n == 0)return modint(1);
	modint res = (a*a) ^ (n / 2);
	if (n % 2)res = res * a;
	return res;
}

//ll inv(ll a, ll p) {
//	return (a == 1 ? 1 : (1 - p * inv(p%a, a)) / a + p);
//}
//modint operator/(modint a, modint b) { return a * modint(inv(b, mod)); }

int dx[4] = { 1,0,-1,0 };
int dy[4] = { 0,1,0,-1 };

int le[5000], ri[5000];

int l[5000], r[5000];
void solve() {
	int n; cin >> n;
	ll x; cin >> x;
	vector<ll> a(n);
	rep(i, n) {
		cin >> a[i];
		le[i] = ri[i] = i;
	}
	rep(i, n) {
		l[i] = r[i] = i;
		ll s = a[i];
		for (int j = i - 1; j >= 0; j--) {
			s += a[j];
			if (s <= x) {
				l[i] = j;
			}
			else break;
		}
		s = a[i];
		for (int j = i + 1; j < n; j++) {
			s += a[j];
			if (s <= x) {
				r[i] = j;
			}
			else break;
		}
	}
	rep1(k, n) {
		rep(i, n - k + 1) {
			int x = i, y = i + k - 1;
			int lr = r[x] + 1;
			bool f = false;
			if (lr >= le[y]) {
				f = true;
			}
			lr = l[y] - 1;
			if (lr <= ri[x]) {
				f = true;
			}
			if (!f) {
				le[y] = x;
				ri[x] = y;
			}
		}
	}
	if (ri[0] == n - 1) {
		cout << "B" << endl;
	}
	else {
		cout << "A" << endl;
	}
}

signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	//cout << fixed << setprecision(5);
	//init();
	//int t; cin >> t; rep(i, t)solve();
	//while (cin >> n, n)solve();
	solve();
	stop
		return 0;
}