#include <iostream>
#include <iomanip>
#include <string>
#include <cmath>

using namespace std;

int main()
{
	string town;
	double sales, comm;

	cin >> town >> sales;

	comm = -1;

	if (town == "Sofia") {
		if (sales < 0) {
			cout << "error" << endl;
		}
		else if (sales >= 0 && sales <= 500) {
			comm = sales * 5 / 100.00;
		}
		else if (sales > 500 && sales <= 1000) {
			comm = sales * 7 / 100.00;
		}
		else if (sales > 1000 && sales <= 10000) {
			comm = sales * 8 / 100.00;
		}
		else if (sales > 10000) {
			comm = sales * 12 / 100.00;
		}
	}
	else if (town == "Varna") {
		if (sales < 0) {
			cout << "error" << endl;
		}
		else if (sales >= 0 && sales <= 500) {
			comm = sales * 4.5 / 100.00;
		}
		else if (sales > 500 && sales <= 1000) {
			comm = sales * 7.5 / 100.00;
		}
		else if (sales > 1000 && sales <= 10000) {
			comm = sales * 10 / 100.00;
		}
		else if (sales > 10000) {
			comm = sales * 13 / 100.00;
		}
	}
	else if (town == "Plovdiv") {
		if (sales < 0) {
			cout << "error" << endl;
		}
		else if (sales >= 0 && sales <= 500) {
			comm = sales * 5.5 / 100.00;
		}
		else if (sales > 500 && sales <= 1000) {
			comm = sales * 8 / 100.00;
		}
		else if (sales > 1000 && sales <= 10000) {
			comm = sales * 12 / 100.00;
		}
		else if (sales > 10000) {
			comm = sales * 14.5 / 100.00;
		}
	}
	else {
		cout << "error" << endl;
	}

	if (comm >= 0) {
		cout << fixed << setprecision(2) << comm << endl;
	}
    return 0;
}