#include "stdafx.h"
#include "stdlib.h"
#include "stdio.h"
#include <iostream>
#include <string>


using namespace std;






int main()
{
	//expresion given by the user
	string expressionToCalc;
	//array to store eqation in RPN
	string reversedPolishNotation[255];
	//get expression from the user
	getline(cin, expressionToCalc);
	expressionToCalc += '\0';
	int onp_iterator = 0;
	string helper = "";

	for (int i = 1; i < expressionToCalc.length(); i++)
	{
		char character = expressionToCalc[i - 1];


		if (character == '0' || character == '1' || character == '2' || character == '3' || character == '4'
			|| character == '5' || character == '6' || character == '7' || character == '8' || character == '9'
			|| character == '-' || character == '+' || character == '*' || character == '/')
		{
			helper += character;

		}


		else if (character == ' ')
		{

			reversedPolishNotation[onp_iterator] = helper;
			onp_iterator++;
			helper.clear();

		}
	}
	reversedPolishNotation[onp_iterator] = helper;


	// calculate value of an expression represented in array
	bool flag = true;
	while (flag) {
		for (int i = 0; i < 255; i++)
		{
			if (reversedPolishNotation[1] == "\0")
			{
				flag = false;
				break;
			}
			if (reversedPolishNotation[i] == "-")
			{
				reversedPolishNotation[i - 2] = to_string(stof(reversedPolishNotation[i - 2]) - stof(reversedPolishNotation[i - 1]));
				i++;
				for (; reversedPolishNotation[i] != "\0"; i++) {
					reversedPolishNotation[i - 2] = reversedPolishNotation[i];
				}
				reversedPolishNotation[i - 2] = reversedPolishNotation[i];
				break;
			}
			if (reversedPolishNotation[i] == "+")
			{
				reversedPolishNotation[i - 2] = to_string(stof(reversedPolishNotation[i - 2]) + stof(reversedPolishNotation[i - 1]));
				i++;
				for (; reversedPolishNotation[i] != "\0"; i++) {
					reversedPolishNotation[i - 2] = reversedPolishNotation[i];
				}
				reversedPolishNotation[i - 2] = reversedPolishNotation[i];
				break;
			}
			if (reversedPolishNotation[i] == "/")
			{
				reversedPolishNotation[i - 2] = to_string(stof(reversedPolishNotation[i - 2]) / stof(reversedPolishNotation[i - 1]));
				i++;
				for (; reversedPolishNotation[i] != "\0"; i++) {
					reversedPolishNotation[i - 2] = reversedPolishNotation[i];
				}
				reversedPolishNotation[i - 2] = reversedPolishNotation[i];
				break;
			}
			if (reversedPolishNotation[i] == "*")
			{
				reversedPolishNotation[i - 2] = to_string(stof(reversedPolishNotation[i - 2]) * stof(reversedPolishNotation[i - 1]));
				i++;
				for (; reversedPolishNotation[i] != "\0"; i++) {
					reversedPolishNotation[i - 2] = reversedPolishNotation[i];
				}
				reversedPolishNotation[i - 2] = reversedPolishNotation[i];
				break;
			}
		}

	}
	cout << reversedPolishNotation[0] << endl;
	system("PAUSE");
	return 0;
}