#include <stdio.h>
double sum (int k, double x)
{
    int i;
    unsigned int h;
    double s, o;
        s = 0;
        o = 1;
        h = 1;
    for (i=0; i<=k;i++)
    {
        if (i) h *= i;
        s += o / h;
        o *= x;
    }
    return(s);
}
int main(void)
{
    int n;
    double h, res;
    scanf_s("%d", &n);
    scanf_s("%lf", &h);
    res = sum(n, h);
    printf("%f", res);
    return(0);
}