from PIL import Image
img = Image.open("xzt.jpg")  
pix = img.load()
def ju(R,G,B):
    gray=0.299*R+0.587*G+0.114*B
    if gray<132:
        return "黑色"
    else:
        return "白色"
def pd(x,y):
    ans=0
    anss=0
    for i in range(x,x+33):
        for j in range(y,y+12):
            R,G,B=pix[i,j]
            if ju(R,G,B)=="黑色":
                ans=ans+1
            anss=anss+1
    if ans/anss>=0.64:
        return "yes"
    else:
        return "no"
yy=1
dic={1:"A",2:"B",3:"C",4:"D"}
for j in range(80,180,45):        
    for k in range(0,4):
        for i in range(83+k*312,1250,60):
            if pd(i,j)=="yes":
                print(dic[yy],end=" ")
                yy=1
                break
            yy=yy+1
    yy=1