using System.Text.Json;

public class Product
{
    public int Id { get; set; }
    public string Name { get; set; }
    public decimal Price { get; set; }
}

class Program
{
    static void Main()
    {
        var product = new Product
        {
            Id = 1,
            Name = "Laptop",
            Price = 1200.99m
        };

        string json = JsonSerializer.Serialize(product);
        Console.WriteLine(json);
    }
}