Problem: Takahashi has a water bottle with the shape of a rectangular prism whose base is a square of side a~\mathrm{cm} and whose height is b~\mathrm{cm}. (The thickness of the bottle can be ignored.)

We will pour x~\mathrm{cm}^3 of water into the bottle, and gradually tilt the bottle around one of the sides of the base.

When will the water be spilled? More formally, find the maximum angle in which we can tilt the bottle without spilling any water.

Constraints

* All values in input are integers.
* 1 \leq a \leq 100
* 1 \leq b \leq 100
* 1 \leq x \leq a^2b

Input

Input is given from Standard Input in the following format:


a b x


Output

Print the maximum angle in which we can tilt the bottle without spilling any water, in degrees. Your output will be judged as correct when the absolute or relative error from the judge's output is at most 10^{-6}.

Examples

Input

2 2 4


Output

45.0000000000


Input

12 21 10


Output

89.7834636934


Input

3 1 8


Output

4.2363947991

Solution (in JAVA):

Solution:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.math.BigDecimal;

public class Main {

	/* several useful subroutines */
	private static BufferedReader brStdin = new BufferedReader(new InputStreamReader(System.in));
	private static String[] readBuf = null;
	private static int readPtr = 0;
	private static String getString() throws IOException {
		while ( readBuf == null || readPtr >= readBuf.length ) {
			readBuf = brStdin.readLine().split(" ");
			readPtr = 0;
		}
		return readBuf[readPtr++];
	}
	private static int getInt() throws IOException {
		return Integer.parseInt(getString());
	}
	private static long getLong() throws IOException {
		return Long.parseLong(getString());
	}
	private static BigDecimal getBD() throws IOException {
		return new BigDecimal(getString());
	}
	@SuppressWarnings("unused")
	private static String[] getStringArray(int size) throws IOException {
		String stringArray[] = new String[size];
		for (int i = 0; i < stringArray.length; i++) {
			stringArray[i] = getString();
		}
		return stringArray;
	}
	@SuppressWarnings("unused")
	private static int[] getIntArray(int size) throws IOException {
		int intArray[] = new int[size];
		for (int i = 0; i < intArray.length; i++) {
			intArray[i] = getInt();
		}
		return intArray;
	}
	@SuppressWarnings("unused")
	private static long[] getLongArray(int size) throws IOException {
		long longArray[] = new long[size];
		for (int i = 0; i < longArray.length; i++) {
			longArray[i] = getLong();
		}
		return longArray;
	}
	@SuppressWarnings("unused")
	private static BigDecimal[] getBDArray(int size) throws IOException {
		BigDecimal bdArray[] = new BigDecimal[size];
		for (int i = 0; i < bdArray.length; i++) {
			bdArray[i] = getBD();
		}
		return bdArray;
	}
	@SuppressWarnings("unused")
	private static long calculateLCM(long a, long b) throws IOException {
		if ( a  < b ) {
			long t = a;
			a = b;
			b = t;
		}
		while ( b > 0 ) {
			long t = b;
			b = a % b;
			a = t;
		}
		return a;
	}

	
	/* main routine */
	
	public static void main(String args[]) throws IOException {
		double a = getInt();
		double b = getInt();
		double x = getInt();
		
		double d ;

		double s = a*a;

		if ( x > s*b/2 ) {
			x = (s*b - x) * 2 / s;
			d = Math.atan(x/a)  / Math.PI * 180 ;
		} else {
			x /= a * b / 2 ;
			d = Math.atan(b/x)   / Math.PI * 180;
		}
		
		
		System.out.println( d );
		
	}
}