module main;

import std.stdio;
import std.algorithm;
import std.range;
import std.bigint;
import std.parallelism;
import std.datetime;

class Timer
{
    static SysTime getCount()
    {
        return Clock.currTime();
    }

    SysTime starttime;

    this() { starttime = getCount(); }
    ~this()
    {
        writefln("elapsed time = %s", getCount() - starttime);
    }
}

const base = 100000;

int main(string[] args)
{
    BigInt result;
    {
        scope t = new Timer();
        result =
            taskPool.reduce!"a * b"(
                map!(fold!"cast(std.bigint.BigInt)a * b")
                    (
                        chunks(
                            iota(1, base + 1),
                            base / totalCPUs / 4
                        )
                    )
            );
    }
    writefln("%s", result);
    return 0;
}