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

#define endl '\n'
#define lfs cout<<fixed<<setprecision(10)
#define ALL(a)  (a).begin(),(a).end()
#define ALLR(a)  (a).rbegin(),(a).rend()
#define spa << " " <<
#define test cout<<"test"<<endl;
#define fi first
#define se second
#define MP make_pair
#define MT make_tuple
#define PB push_back
#define EB emplace_back
#define rep(i,n,m) for(ll i = (n); i < (ll)(m); i++)
#define rrep(i,n,m) for(ll i = (m) - 1; i >= (ll)(n); i--)
using ll = long long;
using ld = long double;
const ll MOD = 1e9+7;
//const ll MOD = 998244353;
const ll INF = 1e18;
using P = pair<ll, ll>;
template<typename T>
void chmin(T &a,T b){if(a>b)a=b;}
template<typename T>
void chmax(T &a,T b){if(a<b)a=b;}
void pmod(ll &a,ll b){a=(a+b)%MOD;}
void pmod(ll &a,ll b,ll c){a=(b+c)%MOD;}
void qmod(ll &a,ll b){a=(a*b)%MOD;}
void qmod(ll &a,ll b,ll c){a=(b*c)%MOD;}
ll median(ll a,ll b, ll c){return a+b+c-max({a,b,c})-min({a,b,c});}
void ans1(bool x){if(x) cout<<"Yes"<<endl;else cout<<"No"<<endl;}
void ans2(bool x){if(x) cout<<"YES"<<endl;else cout<<"NO"<<endl;}
void ans3(bool x){if(x) cout<<"Yay!"<<endl;else cout<<":("<<endl;}
template<typename T1,typename T2>
void ans(bool x,T1 y,T2 z){if(x)cout<<y<<endl;else cout<<z<<endl;}  
template<typename T>
void debug(vector<vector<T>>&v,ll h,ll w){for(ll i=0;i<h;i++)
{cout<<v[i][0];for(ll j=1;j<w;j++)cout spa v[i][j];cout<<endl;}};
void debug(vector<string>&v,ll h,ll w){for(ll i=0;i<h;i++)
{for(ll j=0;j<w;j++)cout<<v[i][j];cout<<endl;}};
template<typename T>
void debug(vector<T>&v,ll n){if(n!=0)cout<<v[0];
for(ll i=1;i<n;i++)cout spa v[i];cout<<endl;};
template<typename T>
vector<vector<T>>vec(ll x, ll y, T w){
  vector<vector<T>>v(x,vector<T>(y,w));return v;}
ll gcd(ll x,ll y){ll r;while(y!=0&&(r=x%y)!=0){x=y;y=r;}return y==0?x:y;}
vector<ll>dx={1,0,-1,0,1,1,-1,-1};
vector<ll>dy={0,1,0,-1,1,-1,1,-1};
template<typename T>
vector<T> make_v(size_t a,T b){return vector<T>(a,b);}
template<typename... Ts>
auto make_v(size_t a,Ts... ts){
  return vector<decltype(make_v(ts...))>(a,make_v(ts...));
}
ostream &operator<<(ostream &os, pair<ll, ll>&p){
  return os << p.first << " " << p.second;
}  
template<typename T>
struct SegmentTree{
  using F = function<T(T,T)>;
  vector<T> data;
  ll n,lastlen = 1;
  F func = [](T a, T b){return a|b;};
  function<bool(T,T)> check = [](T a, T b){return a <= b;};
  T iden = false; //identity element
  SegmentTree(vector<T> &v){
    build(v);
  }
  SegmentTree(ll size){
    build(vector<T>(size, iden));
  }
  void build(vector<T> v){
    n = (ll)v.size();
    while(lastlen < n)lastlen *= 2;
    data.assign(lastlen*2-1,iden);
    for(ll i=0;i<n;i++)data[i+lastlen-1] = v[i];
    for(ll i=lastlen-2;i>=0;i--){
      data[i] = func(data[2*i+1], data[2*i+2]);
    }
  }
  
  void update(ll point, T x){
    point+=lastlen-1;
    data[point] = x;
    while(point!=0){
      point=(point-1)/2;
      data[point]=func(data[2*point+1],data[2*point+2]);
    }
  }
  T query(ll l,ll r){
    T left = iden, right = iden;
    l+=lastlen-1, r+=lastlen-1;
    while(l != r){
      if(~l&1)left = func(left, data[l++]);
      if(~r&1)right = func(data[--r], right);
      l >>= 1,r >>= 1;
    }
    return func(left, right);
  }
  T operator[](ll x){
    return data[lastlen-1+x];
  }
  void print(){
    for(ll i=0;i<n;i++){
      if(i!=0)cout<<" ";
      cout<<data[lastlen-1+i];
    }
    cout<<endl;
  }
  T lower_bound(ll p,T x){
    ll sumbuf=iden, l=p,r=p+1;
    p = p + lastlen - 1;
    while(1){
      if(!check(func(sumbuf,data[p]), x)){
        if(p%2==1){
          p = (p-1)/2;
          r = l + (r-l)*2;
        }
        else if(r>=n){
          return n;
        }
        else{
          func(sumbuf,data[p]);
          p >>= 1;
          ll x = r + (r-l)*2; 
          l = r; r = x;
        }
      }
      else if(p >= lastlen - 1)return r - 1;
      else if(!check(func(sumbuf,data[2*p+1]),x)){
        sumbuf = func(sumbuf, data[2*p+1]);
        p = 2*p+2; l = (r+l)/2;
      }
      else{
        p = 2*p+1; r = (r+l)/2;
      }
    }  
  }
};
int main(){
  cin.tie(nullptr);
  ios_base::sync_with_stdio(false);
  ll res=0,buf=0;
  bool judge = true;
  ll n,x;cin>>n>>x;
  vector<ll>a(n);
  rep(i,0,n)cin>>a[i];
  vector<ll>b(n+1),b2(n+1);
  rep(i,0,n)b[i+1]=b[i]+a[i];
  rep(i,0,n)b2[i+1]=b2[i]+a[n-i-1];
  vector<SegmentTree<bool>>segl,segr;
  rep(i,0,n)segl.EB(n-i);
  rep(i,0,n)segr.EB(i+1);
  //負けはtrue,勝ちはfalse
  rep(i,0,n)rep(j,0,n-i){
    ll l=j,r=i+j;
    bool ret;
    if(i==0)ret=true;
    else if(b[r+1]-b[l]<=x)ret=false;
    else{
      auto idxl=upper_bound(ALL(b),b[l]+x)-b.begin()-l;
      auto idxr=upper_bound(ALL(b2),b2[n-r-1]+x)-b2.begin()-(n-r-1);
      ret=segl[l].query(i-idxr,i)|segr[r].query(i-idxl,i);
      ret^=1;
    }
    //cout<<i spa j spa ret<<endl;
    segl[l].update(i,ret);
    segr[r].update(i,ret);
    if(i==n-1){
      ans(ret,'B','A');
    }
  }
  return 0;
}