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

public class Solution {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        System.out.println("Input the number of seconds with 2 digits after decimal point");
        String z = reader.readLine();
        double t = Double.parseDouble(z);
        float g = 9.81f;
        float h = (float) ((g * t * t) / 2);
        h = Math.round(h * 100.0 / 100.0);
        System.out.println("Depth of well = " + h + " meters");
    }
}