import java.io.*;
import java.util.*;
import java.util.stream.*;

public class Main {
    static long[] sums;
    static boolean[][] wins;
    static boolean[][] used;
    static int x;
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        x = sc.nextInt();
        sums = new long[n + 1];
        for (int i = 1; i <= n; i++) {
            sums[i] = sums[i - 1] + sc.nextInt();
        }
        wins = new boolean[n + 1][n + 1];
        used = new boolean[n + 1][n + 1];
        if (dfw(0, n)) {
            System.out.println("A");
        } else {
            System.out.println("B");
        }
    }
    
    static boolean dfw(int left, int right) {
        if (right - left == 1) {
            return false;
        }
        if (sums[right] - sums[left] <= x) {
            return true;
        }
        if (!used[left][right]) {
            used[left][right] = true;
            for (int i = left + 1; i < right && sums[i] - sums[left] <= x && !wins[left][right]; i++) {
                wins[left][right] = !dfw(i, right);
            }
            for (int i = right - 1; i > left && sums[right] - sums[i] <= x && !wins[left][right]; i--) {
                wins[left][right] = !dfw(left, i);
            }
        }
        return wins[left][right];
    }
}
class Utilities {
    static String arrayToLineString(Object[] arr) {
        return Arrays.stream(arr).map(x -> x.toString()).collect(Collectors.joining("\n"));
    }
    
    static String arrayToLineString(int[] arr) {
        return String.join("\n", Arrays.stream(arr).mapToObj(String::valueOf).toArray(String[]::new));
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public int[] nextIntArray() throws Exception {
        return Stream.of(br.readLine().split(" ")).mapToInt(Integer::parseInt).toArray();
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
    
}