Ex.:

Mr. Davis is number 1111
Mr. Jones is number 2222
Mr. Edison is number 3333

A1=1111
A2=2222
A3=3333

B1=Mr. Davis
B2=Mr. Jones
B3= Mr. Edison

I need the following:

Cell no. 1 : Here I want to type the number of the person
Cell nr. 2: Here I want Excel automatically to write the name of the person corresponding to the number I typed in cell no. 1.

Help is much appreciated.

How is this done?