Price Airport express line for Dongzhimen to Sanyuanqio

Hi,
Saying price of trip is charged according distance, how much is it for Dongzhimen to Sanyuanqiao,
taking Airport express Line please?
How much taken on smart card, because it's not 17 km for Airport terminal...
I'ld like to be sure because it's really much easy to make this route Dongzhimen to Sanyuanqiao directly with Airport express.
Thanks.