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

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

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