What is the voltage I need for the AC/dc power adapter for this monitor?

I'm going to buy a basic power adapter for this monitor. Which one should I buy?

Lenovo - LI2341T 23" IPS LED HD Touch-Screen Monitor - Black

You buy the power adapter from lenovo… If you get it from any other source then it could be the wrong part (even with the correct voltage) or too low wattage and blow out.

It shows the proper part in the manual
http://download.lenovo.com/...tor_ug.pdf
Chapter 3. 3-1
19Vdc --- 3.42A (FSP, FSP065-REB/
Li Shin, PA-1650-52/)
20Vdc --- 2.0A (Liteon, PA-1400-12)
http://www.fsp-group.com.tw/index.php?do=proinfo&id=616
http://www.chargerbuy.com/replacement-lenovo-pa-1650-52lc-ac-adapter-19v-3-42a.html
Data shown. There are other possible.