using System;

using System.Threading;

using System.Threading.Tasks;

public class Program

{

    public static void Main()

    {

        const int iterations = 100000000;

        Parallel.For(1, 9, index => CalculatePi(index, iterations));

    }

    private static decimal CalculatePi(int id, int iterations)

    {

        int counter = 0;

        var random = new Random();

        for (int i = 0; i < iterations; i++ )

        {

            var x = random.NextDouble();

            var y = random.NextDouble();

            var lenghtSquared = x * x + y * y;

            if (lenghtSquared <= 1.0)

            {

                counter++;

            }

        }

        var ratio = (decimal)(counter) / (decimal)(iterations) * 4m;

        Console.WriteLine($"{id}: {ratio}");

        return ratio;

    }

}