You can read "BOROTHER' 1/4 answer,but

來源: 於 2011-01-09 10:14:14 [舊帖] [給我悄悄話] 本文已被閱讀：次

Change X-Y=2M,X*Y=1,

.....

X=2M+Y,...Y<10^(-100)

So,Answer is 0.