import java.math.BigDecimal;
import java.math.MathContext;
import java.math.RoundingMode;

public class Euler722 {
    public static String formatSci12(BigDecimal x) {
        int exponent = 0;
        BigDecimal ten = BigDecimal.TEN;

        while (x.compareTo(ten) >= 0) {
            x = x.divide(ten, 100, RoundingMode.HALF_UP);
            exponent++;
        }
        while (x.compareTo(BigDecimal.ONE) < 0 && x.compareTo(BigDecimal.ZERO) > 0) {
            x = x.multiply(ten);
            exponent--;
        }

        x = x.setScale(12, RoundingMode.HALF_UP);
        if (x.compareTo(ten) >= 0) {
            x = x.divide(ten, 12, RoundingMode.HALF_UP);
            exponent++;
        }
        return x.toString() + "e" + exponent;
    }

    static BigDecimal lnOneMinusX(int p, MathContext mc) {
        BigDecimal x = BigDecimal.ONE.divide(BigDecimal.valueOf(2).pow(p), mc);
        BigDecimal sum = BigDecimal.ZERO;
        BigDecimal term = x;
        int n = 1;
        BigDecimal eps = BigDecimal.ONE.scaleByPowerOfTen(-105);
        while (term.compareTo(eps) > 0) {
            sum = sum.add(term.divide(BigDecimal.valueOf(n), mc), mc);
            n++;
            term = term.multiply(x, mc);
        }
        return sum;
    }

    public static String solve() {
        MathContext mc = new MathContext(110, RoundingMode.HALF_UP);

        int k = 15;
        int p = 25;
        int m = (k + 1) / 2;
        int weight = 2 * m;

        BigDecimal t = lnOneMinusX(p, mc);

        String piStr = "3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679";
        BigDecimal pi = new BigDecimal(piStr, mc);

        BigDecimal y = t.divide(pi.multiply(BigDecimal.valueOf(2), mc), mc);

        BigDecimal b = BigDecimal.valueOf(-3617).divide(BigDecimal.valueOf(510), mc);

        BigDecimal yNegPow = BigDecimal.ONE.divide(y.pow(weight, mc), mc);

        BigDecimal ans = BigDecimal.ONE.subtract(yNegPow, mc).multiply(b, mc).divide(BigDecimal.valueOf(4L * m), mc);

        return formatSci12(ans);
    }

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