#include <iostream>
#include <vector>
#include <string>
#include "std_lib_facilities.h"

void throwError(std::string message){


	std::cout << "-----------------------------------" << std::endl << message << std::endl
		<< "-----------------------------------" << std::endl;

	system("PAUSE");

}

class Token {

public:

	char kind;
	double value;

	Token(char ch)
		:kind(ch), value(0){}

	Token(char ch, double val)
		:kind(ch), value(val){}

};

class Token_stream{

public:

	Token_stream();
	Token get();
	void putBack(Token t);

	private:

		bool full;
		Token buffer;

};

Token_stream::Token_stream()
	:full(false), buffer(0){}

void Token_stream::putBack(Token t){

	if (full) throwError("putBack() into a full buffer");

	buffer = t;
	full = true;

}

Token Token_stream::get(){

	if (full){

		full = false;
		return buffer;

	}

	char ch;

	std::cin >> ch;

	switch (ch){

	case ';': case 'q':
	case '(': case ')': case '+':
	case '-': case '*': case '/':

		return Token(ch);

	case '.':

	case '0': case '1': case '2': case '3': case '4':
	case '5': case '6': case '7': case '8': case '9':{

		std::cin.putback(ch);
		double val;
		std::cin >> val;

		return Token('8', val);

	}

	default:

		throwError("Bad token");

	}
}

Token_stream ts;
double expression();

double primary(){

	Token t = ts.get();
	switch (t.kind){

	case '(': {

		double d = expression();

		t = ts.get();

		if (t.kind != ')'){

			throwError("')' expected");

		}

		return d;

	}

	case '8':

		return t.value;

	default:

		throwError("Primary expected");

	}
}

double term(){

	double left = primary();
	Token t = ts.get();

	while (true){

		switch (t.kind){

		case '*':

			left *= primary();
			t = ts.get();

			break;

		case '/': {

			double d = primary();

			if (d == 0){

				throwError("You cannot divide by 0.");
				break;

			}

			left /= d;
			t = ts.get();

			break;

		}

		default:

			ts.putBack(t);

			return left;

		}
	}
}

double expression(){

	double left = term();
	Token t = ts.get();

	while (true){

		switch (t.kind){

		case '+':

			left += term();
			t = ts.get();

			break;

		case '-':

			left -= term();
			t = ts.get();

			break;

		default:

			ts.putBack(t);

			return left;

		}
	}
}

int main(){

	try{

		double val = 0;

		while (std::cin){

			Token t = ts.get();

			if (t.kind == 'q') break;
			if (t.kind == ';'){

				std::cout << "=" << val << std::endl;

			}else{

				ts.putBack(t);
				val = expression();

			}

			system("PAUSE");
			return 0;

		}
	}
	catch (std::exception& e){

		std::cerr << e.what() << std::endl;

		system("PAUSE");
		return 1;

	}
	catch (...){

		std::cerr << "Exception" << std::endl;

		system("PAUSE");
		return 2;

	}
}