#include <iostream>
#include <string>

using namespace std;

int main()
{
	string fruit, day;
	double quantity;

	cin >> fruit >> day >> quantity;

	double price = 0;

	if (day == "Monday" || day == "Tuesday" || day == "Wednesday" || day == "Thursday" || day == "Friday")
	{
		if (fruit == "banana")
			price = 2.50;
		else if (fruit == "apple")
			price = 1.20;
		else if (fruit == "orange")
			price = 0.85;
		else if (fruit == "grapefruit")
			price = 1.45;
		else if (fruit == "kiwi")
			price = 2.70;
		else if (fruit == "pineapple")
			price = 5.50;
		else if (fruit == "grapes")
			price = 3.85;
		else
			cout << "error" << endl;

		cout.setf(ios::fixed);
		cout.precision(2);
		cout << price * quantity << endl;
	}
	else if (day == "Saturday" || day == "Sunday")
	{
		if (fruit == "banana")
			price = 2.70;
		else if (fruit == "apple")
			price = 1.25;
		else if (fruit == "orange")
			price = 0.90;
		else if (fruit == "grapefruit")
			price = 1.60;
		else if (fruit == "kiwi")
			price = 3;
		else if (fruit == "pineapple")
			price = 5.60;
		else if (fruit == "grapes")
			price = 4.20;
		else
			cout << "error" << endl;

		cout.setf(ios::fixed);
		cout.precision(2);
		cout << price * quantity << endl;
	}
	else
	{
		cout << "error" << endl;
	}
	return 0;
}