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():
    n,x=MI()
    aa=LI()
    dp=[[0]*(n+1) for _ in range(n+1)]
    for l in range(n):dp[l][l]=True
    for l in range(n):dp[l][l+1]=False
    for d in range(2,n+1):
        for l in range(n-d+1):
            r=l+d
            v=False
            s=0
            for nl in range(l+1,r):
                s+=aa[nl-1]
                if s>x:break
                if not dp[nl][r]:
                    v=True
                    break
            s=0
            for nr in range(r-1,l,-1):
                if v:break
                s+=aa[nr]
                if s>x:break
                if not dp[l][nr]:
                    v=True
                    break
            dp[l][r]=v

    #p2D(dp)
    if dp[0][n]:print("A")
    else:print("B")

main()