I have information on two excel sheets/tabs

One sheet is where i want to input data

the other sheet is where i want it to grab the info.

So if I put in 3 in A1, it will look on the second sheet and grab a number from B3 and place this number in A2 (on the first sheet).

If I put in 2 in A1, it will look on the second sheet and grab a number from B2 and place this number in A2 (on the first sheet).

I was able to figure out how to it for one number, but if you ask other numbers it doesn't work.

=IF(A1=3,Sheet2!B3)

so that formula works for the number 3. what if I put in the number 2 or 9 or 211?

Any suggestions?