import java.util.*;
import java.io.*;
import java.math.*;

public class pi_estimator {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		
		long z=0, n=1000000; 
		double x, y, pi;
		
		Random rnd = new Random();

		for (long i=0; i < n; ++i) {
			x = rnd.nextDouble();
			y = rnd.nextDouble();
			if (Math.sqrt(x*x + y*y) <= 1) z++;
		}
		
		pi = 4.0*z/n;
		System.out.println("Pi is estimated to be " + pi);

	}

}