R you Being Cautious?

Fill the grid with the digits from 1 to 6 and the letters R, B and C such that each row, column and 3x3 region contains each symbol once. Symbols in a killer cage do not repeat and sum to the little clue in the top left. The letter R counts as the row number of its cell. B counts as the box number of its cell. C counts as the column number of its cell. (Note that although symbols in a cage do not repeat, different symbols may contribute the same value to the sum.)