public class Euler587 {
    static double concave_ratio(long n) {
        double nl = (double) n;
        double s2n = Math.sqrt(2.0 * nl);
        double x0 = nl * (nl + 1.0 - s2n) / (nl * nl + 1.0);

        double d = 1.0 - x0;
        double root = Math.sqrt(Math.max(0.0, 1.0 - d * d));

        double area_line = x0 * x0 / (2.0 * nl);
        double area_arc = d - 0.5 * (d * root + Math.asin(d));
        double area_concave = area_line + area_arc;

        double area_L = 1.0 - Math.PI / 4.0;
        return area_concave / area_L;
    }

    public static String solve() {
        long n = 1;
        while (true) {
            if (concave_ratio(n) < 0.001) {
                return Long.toString(n);
            }
            n++;
        }
    }

    public static void main(String[] args) {
        System.out.println(solve());
    }
}