// Arup Guha
// 8/3/2026
// Solution to 1990 UCF HS Programming Contest Problem: Yo!

import java.util.*;

public class toys {
	
	// They did this in the old days!
	final public static double PI = 3.14159;
	
	public static void main(String[] args) {
	
		Scanner stdin = new Scanner(System.in);	
		while (stdin.hasNext()) {
		
			double dSpin = stdin.nextDouble();
			double dYo = stdin.nextDouble();
			double len = stdin.nextDouble();
			
			// The only part that doesn't spin around the spindle is one radius
			// of the yo, so subract this out.
			len -= (dYo/2);
			
			// Use definition of PI to get one revolution distance.
			double oneRev = dSpin*PI;
			
			// Percent formatting, it's the best...
			System.out.printf("Yo will make %6.2f revolutions before jerking to a halt!\n", len/oneRev);
		}
	}
}