#include<cstdio>#include<cstring>#include<algorithm>#define maxn 32using namespace std;int n;double p[maxn],t;void pre(){    p[0]=1;    for(int i=1;i<=30;i++)        p[i]=p[i-1]*2.0;}double solve(){    double f=p[n];    for(int i=n-1;i>=0;i--)    {        double eq=p[i]/f;        if(eq<t)            f=(1+t)*f/2.0;        else            f=(eq-t)*p[i]/(1-t)+(1-eq)*(eq+1)*f/(1-t)/2.0;    }    return f;}int main(){    pre();    while(scanf("%d%lf",&n,&t)&&n)    {        printf("%.3lf\n",solve());    }    return 0;}