enter text to cells with special style

I have defined four different styles (colors: blue, red, yellow, green) and I want to add four different texts specially defined for each cell with the specially defined cell-style.

Something like this,

So: -r for the blue, -e for red and green, -s for the yellow; these strings should be added to the beginning of each cell. It’s really time consuming to add them manually, as you see, rows are too many.

This looks really strange. There is a suspicion strongly suggsting itself: You want to support a specific functionality and chose an unsuitable way.
Most likely you would better dedicate a column to the markers ("-r", “-e”, “-s”, …) and then apply the coloring by a Conditional Format you define properly.
It’s always bad to code for relevant information by setting cell attributes.
If you want to redesign your sheet the way I described I can advise you.