Suppose you have the unique solution to this Sudoku puzzle. In that solution, let \mathfrak{X} denote the sum of all digits in the shaded grey squares. Similarly, let \mathfrak{Y} denote the sum of all numbers in the shaded yellow squares on the upper left block (i.e. the 3 \times 3 box outlined red towards the top left). Concatenate \mathfrak{X} with \mathfrak{Y} in that order, and write that down.