#include <iostream>
#include <cstdlib>
using namespace std;

int main()
{
        double miles {0.0};
	cout << "How many miles was your cab ride?\n";
	cin >>miles;

	if (!cin) {
		cerr << "Sorry, that wasn't a valid number.\n";
		return EXIT_FAILURE;   //miles die here.
}


	if (miles <= 0 || miles >= 100) {
		cerr << "sorry, that wasn't a legitimate number.\n";
		return EXIT_FAILURE; 
	}

		
	

	//Formula for taxi ride in nyc.
	 double dollars {3.00 + 3.50 * miles};

	cout << "Your cab ride costs  "
		<< dollars <<  "dollars.\n";
	return EXIT_SUCCESS;   //pounds and minutes die here.
}