/**

 对于大数的很好的应用，，缩小放大，，保持精度

 **/

 #include <iostream>

 #include <cmath>

 #include <algorithm>

 #include <cstdio>

 using namespace std;

 int main()

 {

     double n,p;

     int cnt =;

     while(cin>>n>>p){

         double p1 = log(p+0.0);

         double p2 = log(-p+0.0);

         double s1 = (n+)*p1;

         double s2 = (n+)*p2;

         double ans =,c=;

         for(int i=;i<n;i++){

             ans += (exp(c+s1)+exp(c+s2))*(n-i);

             c += log(n++i+0.0)-log(i++0.0);

             s1 += p2;

             s2 += p1;

         }

         printf("Case %d: %.6lf\n",cnt++,ans);

     }

     return ;

 }