n, x = map(int, input().split())
a = list(map(int, input().split()))

ruiseki = [0] * (n + 1)
for i in range(n):
    ruiseki[i + 1] = ruiseki[i] + a[i]
    

def solve(l, r):
    # [l, r)のシュークリームが残っているときの先手の勝ち負け
    if r - l == 0:
        dp[l][r] = True
        return True
    if r - l == 1:
        dp[l][r] = False
        return False
    if dp[l][r] is not None:
        return dp[l][r]

    tmp = False
    for newl in range(l + 1, r + 1):
        if ruiseki[newl] - ruiseki[l] <= x:
            tmp |= not solve(newl, r)
    for newr in range(l, r):
        if ruiseki[r] - ruiseki[newr] <= x:
            tmp |= not solve(l, newr)
    dp[l][r] = tmp
    
    return tmp

dp = [[0] * (n + 1) for i in range(n + 1)]
if solve(0, n):
    print("A")
else:
    print("B")