OPZ_9

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

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] opz;
            using (var sr = new StreamReader("input.txt"))
            {
                opz = sr.ReadLine().Split(' ');
            }
            Stack<double> numbers = new Stack<double>();
            for (int i = 0; i < opz.Length; i++)
            {
                switch(opz[i])
                {
                    case "+":
                        double a = numbers.Pop();
                        double b = numbers.Pop();
                        numbers.Push(b + a);
                        break;
                    case "-":
                        a = numbers.Pop();
                        b = numbers.Pop();
                        numbers.Push(b - a);
                        break;
                    case "/":
                        a = numbers.Pop();
                        b = numbers.Pop();
                        numbers.Push(b / a);
                        break;
                    case "*":
                        a = numbers.Pop();
                        b = numbers.Pop();
                        numbers.Push(b * a);
                        break;
                    case "^":
                        a = numbers.Pop();
                        b = numbers.Pop();
                        numbers.Push(Math.Pow(b, a));
                        break;
                    default: //значения
                        numbers.Push(double.Parse(opz[i]));
                        break;
                }
            }
            Console.WriteLine(numbers.Peek());
            Console.ReadKey();
        }
    }
}