package zhidao;
public class Calc
{
public static void main ( String[] args )
{
System.out.println (calc (100));
}
private static double calc ( int n )
{
if (n == 1)
{
return 1 / 1.d;
}
else
{
return Math.pow (-1, n - 1) * 1.d / n + calc (n - 1);
}
}
}