#include <bits/stdc++.h>
using namespace std;
#define modulo 1000000007
#define mod(mod_x) ((((long long)mod_x+modulo))%modulo)
#define Inf 10000000000000000



int main(){
	
	int N,X;
	cin>>N>>X;
	
	vector<int> a(N);
	for(int i=0;i<N;i++){
		cin>>a[i];
	}
	
	vector<vector<bool>> dp(N,vector<bool> (N,true));
	
	for(int i=0;i<N;i++){
		for(int j=0;j<N;j++){
			int l = j;
			int r = j+i;
			if(r>=N)break;
			int sum = 0;
			bool now = true;
			while(true){
				sum += a[l];
				if(sum>X)break;
				l++;
				if(l>r)break;
				now &= dp[l][r];
				if(!now)break;
			}
			
			l = j;
			r = j+i;
			sum = 0;
			while(true){
				sum += a[r];
				if(sum>X)break;
				r--;
				if(l>r)break;
				now &= dp[l][r];
				if(!now)break;
			}
			dp[j][j+i]=!now;
		}		
	}

	
	if(!dp[0][N-1]){
		cout<<"B"<<endl;
	}
	else{
		cout<<"A"<<endl;
	}
	
	


	return 0;
}