第4关：求三角形的面积

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ch204
{
    class Program
    {
        static void Main(string[] args)
        {
			/******begin*******/
			double a, b, c, s, area;
            a = Convert.ToInt32(Console.ReadLine());
            b = Convert.ToInt32(Console.ReadLine());
            c = Convert.ToInt32(Console.ReadLine());
            s = (a + b + c) / 2;
            area = Math.Sqrt(s * (s - a) * (s - b) * (s - c));
            Console.WriteLine("s={0}", area);
			
			
			/*******end********/

        }
    }
}