Scanf.scanf "%d" (fun k ->
    let arr = Array.make 201 0 in
    Array.iter (fun a ->
        Array.iter (fun b ->
            let c = a * b in
            arr.(c) <- arr.(c) + 1
        ) [| 4; 6; 8; 9; 10; 12 |]
    ) [| 2; 3; 5; 7; 11; 13 |];
    Printf.printf "%.12f\n" (float arr.(k) /. 36.)
)