import java.io.*;
import hsa.Console;
import java.util.Arrays;
import java.util.StringTokenizer;
import java.lang.Math;

// The "Template" class.
public class FILE_TEMP
{
    static FileReader inFile;
    static FileWriter outFile;

    // Link the input and output file for
    static BufferedReader in;
    static BufferedWriter out;


    public static void main (String[] args) throws IOException
    {

	// Open up the input and output file for IO purpose

	inFile = new FileReader ("DATA1.txt");
	outFile = new FileWriter ("OUT1.txt");

	// Link the input and output file for
	in = new BufferedReader (inFile);
	out = new BufferedWriter (outFile);


	String x1 = "";
	String x2 = "";
	String y1 = "";
	String y2 = "";
	String line = "";
	StringTokenizer st;
	int X1, X2, Y1, Y2;
	double xBegin, xEnd, yBegin, yEnd;
	double angle1, angle2, Angle;

	// Keep reading as long as not end of file (eof)
	while ((line = in.readLine ()) != null)
	{
	    st = new StringTokenizer (line);
	    while (st.hasMoreTokens ())
	    {
		x1 = (st.nextToken ());
		//System.out.println (x1);
		y1 = (st.nextToken ());
		//System.out.println (x2);
		x2 = (st.nextToken ());
		//System.out.println (y1);
		y2 = (st.nextToken ());
	    }

	    // make into ints
	    X1 = Integer.parseInt (x1);
	    //System.out.println (X1);
	    X2 = Integer.parseInt (x2);
	    Y1 = Integer.parseInt (y1);
	    Y2 = Integer.parseInt (y2);

	    // make into doubles
	    xBegin = (double) X1;
	    //System.out.println (xBegin);
	    xEnd = (double) X2;
	    yBegin = (double) Y1;
	    yEnd = (double) Y2;

	    angle1 = Math.atan (Math.abs (yBegin) / Math.abs (xBegin));
	    angle2 = Math.atan (Math.abs (yEnd) / Math.abs (xEnd));
	    //System.out.println (angle1);
	    //System.out.println (angle2);
	    if (Math.abs (xBegin) < Math.abs (xEnd))
	    {
		Angle = angle1 - angle2;
		Angle = Math.toDegrees (Angle);
		//System.out.println (Angle);
		out.write ("" + Angle);
		out.newLine();
	    }
	    else if (Math.abs (xBegin) > Math.abs (xEnd))
	    {
		Angle = 2 * Math.PI + angle1 - angle2;
		//System.out.println (Angle);
		Angle = Math.toDegrees (Angle);
		out.write ("" + Angle);
		out.newLine();

	    }
	    else if (xBegin == xEnd || yBegin == yEnd)
	    {
		Angle = 180.0;
		out.write ("" + Angle);
		out.newLine();

	    }
	    else if (xBegin == xEnd && yBegin == yEnd)
{
		Angle = 360.0;
		out.write ("" + Angle);
		out.newLine();

	    }


	}
	out.flush ();
	out.close ();
    }
} // main method
// End of Class