#include <iostream>
#include <sstream>
#include <vector>

std::vector<std::string> split(const std::string &s, char delim) {
	std::vector<std::string> elems;
    std::stringstream ss;
    ss.str(s);
    std::string item;
    while (std::getline(ss, item, delim)) {
        elems.push_back(item);
    }
    return elems;
}

struct Rect {
	double x1, x2, y1, y2;
	void operator << (std::string line) {
		auto rectcoods = split(line, ' ');
		this->x1 = std::stod(split(rectcoods.at(0), ',').at(0));
		this->y1 = std::stod(split(rectcoods.at(0), ',').at(1));
		this->x2 = std::stod(split(rectcoods.at(1), ',').at(0));
		this->y2 = std::stod(split(rectcoods.at(1), ',').at(1));
	}

	double area() {
		return ((std::max(x1,x2)- std::min(x1,x2))*(std::max(y1,y2) - std::min(y1,y2)));
	}
};

Rect getIntersectionRect(Rect rect1, Rect rect2) {
	Rect result;
	result.x1 = std::max(std::min(rect1.x1, rect1.x2), std::min(rect2.x1, rect2.x2));
	result.x2 = std::min(std::max(rect1.x1, rect1.x2), std::max(rect2.x1, rect2.x2));
	result.y1 = std::min(std::max(rect1.y1, rect1.y2), std::max(rect2.y1, rect2.y2));
	result.y2 = std::max(std::min(rect1.y1, rect1.y2), std::min(rect2.y1, rect2.y2));

	return result;
}

double getIntersectionArea(Rect rect1, Rect rect2) {
	double height = std::min(std::max(rect1.y1, rect1.y2), std::max(rect2.y1, rect2.y2)) - std::max(std::min(rect1.y1, rect1.y2), std::min(rect2.y1, rect2.y2));
	double width  = std::min(std::max(rect1.x1, rect1.x2), std::max(rect2.x1, rect2.x2)) - std::max(std::min(rect1.x1, rect1.x2), std::min(rect2.x1, rect2.x2));

	return(std::max(height, double(0)) * std::max(width, double(0)));
}

int main() {
	std::vector<Rect> rects;

	std::string line;
	while(std::getline(std::cin, line) && !line.empty()) {
		Rect rect;
		rect << line;
		rects.push_back(rect);
	}

	Rect currentIntersectionRect = rects.at(0);
	bool done = false;
	double solution = 0;
	for (auto rect : rects){
		if (getIntersectionArea(currentIntersectionRect, rect) == 0) {
			done = true; break;
		}
		currentIntersectionRect = getIntersectionRect(currentIntersectionRect,rect);
	}

	if(!done) {solution = currentIntersectionRect.area();}

	std::cout << solution << std::endl;
}