import sys

sys.setrecursionlimit(10 ** 6)
int1 = lambda x: int(x) - 1
p2D = lambda x: print(*x, sep="\n")
def II(): return int(sys.stdin.readline())
def MI(): return map(int, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]

def main():
    def win(l,r):
        if dp[l][r]!=None:return dp[l][r]
        if l+1==r:return False
        if l==r:return True
        res=False
        s=0
        for nl in range(l+1,r):
            s+=aa[nl-1]
            if s>x:break
            if not win(nl,r):
                res=True
                break
        s=0
        for nr in range(r-1,l,-1):
            if res:break
            s+=aa[nr]
            if s>x:break
            if win(l,nr)==0:
                res=1
                break
        dp[l][r]=res
        return res

    n,x=MI()
    aa=LI()
    dp=[[None]*(n+1) for _ in range(n+1)]
    if win(0,n):print("A")
    else:print("B")

main()