procedure main(A)
   \A | stop("You must give one or more numeric values")
   every n := !A do write(n," is ",(damm(n),"valid")|"not valid")
end

procedure damm(n)
   static grid
   initial grid := [[0, 3, 1, 7, 5, 9, 8, 6, 4, 2],
                    [7, 0, 9, 2, 1, 5, 4, 8, 6, 3],
                    [4, 2, 0, 6, 8, 7, 1, 3, 5, 9],
                    [1, 7, 5, 0, 9, 8, 3, 4, 2, 6],
                    [6, 1, 2, 3, 0, 4, 5, 9, 7, 8],
                    [3, 6, 7, 4, 2, 0, 9, 5, 8, 1],
                    [5, 8, 6, 9, 7, 2, 0, 1, 3, 4],
                    [8, 9, 4, 5, 3, 6, 2, 0, 1, 7],
                    [9, 4, 3, 8, 6, 1, 7, 2, 0, 5],
                    [2, 5, 8, 1, 4, 3, 6, 7, 9, 0]]
    interim := 0
    every d := !n do interim := grid[interim+1][d+1]
    return 0 = interim
end