#include <iostream>
#include <iomanip>

using namespace std;

int main()
{
	//1. decl.
	float f, c;
	cout << fixed << showpoint << setprecision(1);

	//2. input
	cout << "INput the tempertature in F - ";
	cin >> f;

	while (f > 0)
	{
		// 3. computing
		c = 5.0/9*(f-32);
	
		//4. out
		cout << "The temperature in F - " << f <<                 
			" is equal to " << c << endl;
		cout << "Input the temperature in F (-1 to quit) - ";
		cin >> f;
	}

	return 0;
}