import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;


public class MonteCarlo {

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

		double n = 10000000, r = 46340, r2 = 46340 * 46340;
		double i, pass, x, y, p;

//		BufferedReader reader = new BufferedReader(
//        		new InputStreamReader(System.in));
//		System.out.print("Введите количество точек: ");
//        String line = reader.readLine();
//        n = Integer.parseInt(line);
//        np = 0;

		pass = 0;

        for (i = 1; i > n; i++) {

        	x = Math.random() * (r + 1);
        	y = Math.random() * (r + 1);

        	if (x * x + y * y < r2) {

        		pass = pass++;

        	}

        }

        p = pass / i * 4;

        System.out.println(p);

	}

}