Problem: Dima is living in a dormitory, as well as some cockroaches.

At the moment 0 Dima saw a cockroach running on a table and decided to kill it. Dima needs exactly T seconds for aiming, and after that he will precisely strike the cockroach and finish it.

To survive the cockroach has to run into a shadow, cast by round plates standing on the table, in T seconds. Shadow casted by any of the plates has the shape of a circle. Shadow circles may intersect, nest or overlap arbitrarily.

The cockroach uses the following strategy: first he equiprobably picks a direction to run towards and then runs towards it with the constant speed v. If at some moment t ≤ T it reaches any shadow circle, it immediately stops in the shadow and thus will stay alive. Otherwise the cockroach is killed by the Dima's precise strike. Consider that the Dima's precise strike is instant.

Determine the probability of that the cockroach will stay alive.

Input

In the first line of the input the four integers x0, y0, v, T (|x0|, |y0| ≤ 109, 0 ≤ v, T ≤ 109) are given — the cockroach initial position on the table in the Cartesian system at the moment 0, the cockroach's constant speed and the time in seconds Dima needs for aiming respectively.

In the next line the only number n (1 ≤ n ≤ 100 000) is given — the number of shadow circles casted by plates.

In the next n lines shadow circle description is given: the ith of them consists of three integers xi, yi, ri (|xi|, |yi| ≤ 109, 0 ≤ r ≤ 109) — the ith shadow circle on-table position in the Cartesian system and its radius respectively.

Consider that the table is big enough for the cockroach not to run to the table edges and avoid Dima's precise strike.

Output

Print the only real number p — the probability of that the cockroach will stay alive.

Your answer will be considered correct if its absolute or relative error does not exceed 10 - 4.

Examples

Input

0 0 1 1
3
1 1 1
-1 -1 1
-2 2 1


Output

0.50000000000

Input

0 0 1 0
1
1 0 1


Output

1.00000000000

Note

The picture for the first sample is given below. 

<image>

Red color stands for points which being chosen as the cockroach's running direction will cause him being killed, green color for those standing for survival directions. Please note that despite containing a circle centered in ( - 2, 2) a part of zone is colored red because the cockroach is not able to reach it in one second.

Solution (in JAVA):

Solution:
//package round357;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.Comparator;
import java.util.InputMismatchException;

public class E {
	InputStream is;
	PrintWriter out;
	String INPUT = "";
	
	void solve()
	{
		long x0 = ni(), y0 = ni(), v = ni(), T = ni();
		int n = ni();
		
		double[][] es = new double[4*n][];
		int p = 0;
		for(int i = 0;i < n;i++){
			long x = ni()-x0, y = ni()-y0, r = ni();
			// x^2+y^2 >= (vT+r)^2
			if(x*x+y*y <= r*r){
				out.println(1);
				return;
			}
			if(x*x+y*y > (double)(v*T+r)*(v*T+r)){
				continue;
			}
			double d = Math.sqrt(x*x+y*y);
			double base = Math.atan2(y, x);
			double e = Math.sqrt(x*x+y*y-r*r);
			double wing = 0;
			if(e <= v*T){
				wing = Math.asin(r/d);
			}else{
				double ac = ((double)(v*T)*(v*T)+(x*x+y*y)-r*r)/(2.*v*T*d);
				if(ac >= 1)ac = 1;
				if(ac <= -1)ac = -1;
				wing = Math.acos(ac);
			}
			double inf = base - wing;
			double sup = base + wing;
			for(double u = -4*Math.PI, w = -2*Math.PI;w <= 4*Math.PI;u +=  2*Math.PI, w += 2 * Math.PI){
				if(Math.max(inf, u) < Math.min(sup, w)){
					es[p++] = new double[]{Math.max(inf, u)-u, 1};
					es[p++] = new double[]{Math.min(sup, w)-u, -1};
				}
			}
		}
		Arrays.sort(es, 0, p, new Comparator<double[]>() {
			public int compare(double[] a, double[] b) {
				return Double.compare(a[0], b[0]);
			}
		});
		double pre = 0;
		int h = 0;
		double ret = 0;
		for(int i = 0;i < p;i++){
			if(h > 0){
				ret += es[i][0]-pre;
			}
			pre = es[i][0];
			h += (int)es[i][1];
		}
		out.printf("%.14f\n", ret/(2*Math.PI));
	}
	
	
	
	void run() throws Exception
	{
//		int n = 100000, m = 99999;
//		Random gen = new Random();
//		StringBuilder sb = new StringBuilder();
//		sb.append(1000000000 + " ");
//		sb.append(1000000000 + " ");
//		sb.append(0 + " ");
//		sb.append(1000000000 + " ");
//		sb.append(n + " ");
//		for (int i = 0; i < n; i++) {
//			sb.append(gen.nextInt(2000000000)-1000000000 + " ");
//			sb.append(gen.nextInt(2000000000)-1000000000 + " ");
//			sb.append(gen.nextInt(101) + " ");
//		}
//		INPUT = sb.toString();

		
		is = oj ? System.in : new ByteArrayInputStream(INPUT.getBytes());
		out = new PrintWriter(System.out);
		
		long s = System.currentTimeMillis();
		solve();
		out.flush();
		tr(System.currentTimeMillis()-s+"ms");
	}
	
	public static void main(String[] args) throws Exception { new E().run(); }
	
	private byte[] inbuf = new byte[1024];
	private int lenbuf = 0, ptrbuf = 0;
	
	private int readByte()
	{
		if(lenbuf == -1)throw new InputMismatchException();
		if(ptrbuf >= lenbuf){
			ptrbuf = 0;
			try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }
			if(lenbuf <= 0)return -1;
		}
		return inbuf[ptrbuf++];
	}
	
	private boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
	private int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }
	
	private double nd() { return Double.parseDouble(ns()); }
	private char nc() { return (char)skip(); }
	
	private String ns()
	{
		int b = skip();
		StringBuilder sb = new StringBuilder();
		while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ')
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	
	private char[] ns(int n)
	{
		char[] buf = new char[n];
		int b = skip(), p = 0;
		while(p < n && !(isSpaceChar(b))){
			buf[p++] = (char)b;
			b = readByte();
		}
		return n == p ? buf : Arrays.copyOf(buf, p);
	}
	
	private char[][] nm(int n, int m)
	{
		char[][] map = new char[n][];
		for(int i = 0;i < n;i++)map[i] = ns(m);
		return map;
	}
	
	private int[] na(int n)
	{
		int[] a = new int[n];
		for(int i = 0;i < n;i++)a[i] = ni();
		return a;
	}
	
	private int ni()
	{
		int num = 0, b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private long nl()
	{
		long num = 0;
		int b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private boolean oj = System.getProperty("ONLINE_JUDGE") != null;
	private void tr(Object... o) { if(!oj)System.out.println(Arrays.deepToString(o)); }
}