import sys
input = sys.stdin.readline

N,X=map(int,input().split())
A=list(map(int,input().split()))

DP=[[0]*N for i in range(N)]

for l in range(N-1):
    for i in range(N-l):
        j=i+l
        if DP[i][j]==0:
            w=0
            for k in range(j+1,N):
                w+=A[k]
                if w<=X:
                    DP[i][k]=1
                else:
                    break

            w=0
            for k in range(i-1,-1,-1):
                w+=A[k]
                if w<=X:
                    DP[k][j]=1
                else:
                    break

if DP[0][N-1]==1:
    print("A")
else:
    print("B")