class Main
{
	public static void main (String[] args) 
	{
		java.util.Scanner in = new java.util.Scanner(System.in);
		int a = in.nextInt(), b = in.nextInt(), n = in.nextInt(), k;
		k = (int)Math.ceil((double)(n - b) / (b - a));
		System.out.println(2 * k + 1);
	}
}