#include <string>
#include <stack>
#include <iostream>
#include <cctype>
#include <cstdlib>

void superPop(std::stack<double>&stck, double *first, double *second) {
	*second = stck.top();
	stck.pop();
	*first = stck.top();
	stck.pop();
}

void addition(std::stack<double> &stck) {
	double nbr1, nbr2;
	superPop(stck, &nbr1, &nbr2);

	stck.push(nbr1 + nbr2);
}

void subtraction(std::stack<double> &stck) {
	double nbr1, nbr2;
	superPop(stck, &nbr1, &nbr2);

	stck.push(nbr1 - nbr2);
}

void multiplication(std::stack<double> &stck) {
	double nbr1, nbr2;
	superPop(stck, &nbr1, &nbr2);

	stck.push(nbr1 * nbr2);
}

void division(std::stack<double> &stck) {
	double nbr1, nbr2;
	superPop(stck, &nbr1, &nbr2);

	if (nbr1 == 0 || nbr2 == 0) {
		std::cout << "Error: Can't divise by 0" << std::endl;
		throw std::exception();
	}

	stck.push(nbr1 / nbr2);
}

int main(int argc, char **argv) {

	if (argc != 2) {
		std::cout << "Error: Number of argument is wrong" << std::endl;
		return 1;
	}

	std::stack<double> stck;
	std::string cal(argv[1]);
	bool spaced = false;

	for (size_t i = 0; i < cal.size(); i++) {
		char c = cal[i];
		if (spaced && c != ' ') {
			std::cout << "Error: Only one character by character" << std::endl;
			return 1;
		}
		else if (!spaced) {
			if (std::isdigit(c))
				stck.push(std::atoi(&c));
			else if (stck.size() <= 1) {
				std::cout << "Error: Too much operator" << std::endl;
				return 1;
			}
			else if (c == '+')
				addition(stck);
			else if (c == '-')
				subtraction(stck);
			else if (c == '*')
				multiplication(stck);
			else if (c == '/') {
				try {
					division(stck);
				}
				catch (std::exception &e) {
					return 1;
				}
			}
			else {
				std::cout << "Error: Bad Input '" << c << "'" << std::endl;
				return 1;
			}
		}
		spaced = !spaced;
	}
	double result = stck.top();
	stck.pop();
	if (!stck.empty()) {
		std::cout << "Error" << std::endl;
		return 1;
	}
	std::cout << result << std::endl;
	return 0;
}