type int_array = array of int

function init_grid() : int_array =
(
  let
    var n := 81
    var grid := int_array[n] of 0
  in
    grid[0] := 2;
    grid[4] := 1;
    grid[8] := 8;
    grid[13] := 7;
    grid[14] := 9;
    grid[16] := 4;
    grid[17] := 5;
    grid[23] := 6;
    grid[24] := 1;
    grid[25] := 3;
    grid[31] := 9;
    grid[34] := 5;
    grid[37] := 4;
    grid[38] := 7;
    grid[40] := 5;
    grid[42] := 8;
    grid[43] := 1;
    grid[46] := 1;
    grid[49] := 8;
    grid[55] := 7;
    grid[56] := 9;
    grid[57] := 5;
    grid[63] := 4;
    grid[64] := 8;
    grid[66] := 9;
    grid[67] := 2;
    grid[72] := 5;
    grid[76] := 3;
    grid[80] := 4;

    grid
  end
)