I need to create a conditional formatting,

I need to hightlight from A1:A18

In the above cells I have values from 1 to 4

So I need to fill the cell with 4 different colours.

If cell equals 1 = Green
If cell equals 2 = Yellow
If cell equals 3 = Red
If cell equals 4 = Blue

What I do is highlight cell from A1:A18, clik on 'Format', 'Conditional Formatting', I've tried using 'Cells Value is' and 'Formula is'.... but with no luck

Can anyone help

See attached file. Hope it helps