#load "nums.cma";;

open Big_int;;

let est_carre_parfait n =
    let v = (floor (sqrt n)) in

    (v *. v = n)
;;


let calcule () =
    let sper = ref (big_int_of_int (0)) in

    for a = 1 to 333333333 do
        if (a mod 1000000) = 0
            then begin
                print_int a;
                print_string "\n"
                end;

        let af = float_of_int a in
        let s1 = (af +. af +. af +. 1.) /. 2. in
        let s2 = (af +. af +. af -. 1.) /. 2. in

        let ac1 = s1 *. (s1 -. af) *. (s1 -. af) *. (s1 -. (af +. 1.)) in
        let ac2 = s2 *. (s2 -. af) *. (s2 -. af) *. (s2 -. (af -. 1.)) in

        if est_carre_parfait ac1
            then begin
                (*Printf.printf "%d %d %d\n" a a (a+1);*)

                if ac1 > 0. then
                    sper := add_big_int (!sper) (big_int_of_int (a + a + a + 1))

                end;
        if est_carre_parfait ac2
            then begin
                (*Printf.printf "%d %d %d\n" a a (a-1);*)

                 if ac2 > 0. && (a-1) > 0 then
                    sper := add_big_int (!sper) (big_int_of_int (a + a + a - 1))
                end
    done;

    !sper
;;



Printf.printf "%s\n" (string_of_big_int (calcule ()));;