int main ()
{
    int m,s,n,i;
    float a1=2,a2=3,b1=1,b2=2,a,b,sum=3.5;
    scanf("%d",&m);

   for(s=0;s<m;s++)  
   {
   scanf("%d",&n);
   if (n==1)
     printf("2.000\n");
  else {if (n==2)
    printf("3.500\n");
  else {
    for (i=3;i<=n;i++)
    {
        a=a1+a2;
        b=b1+b2;
        sum=sum+a/b;
        a1=a2;a2=a;
        b1=b2;b2=b; 
        
        }  
          printf("%.3f\n",sum);} 
          
          sum=3.5;
         a1=2;a2=3;b1=1;b2=2;
         
    }
    } 
return 0;
    } 
