1 #include <stdio.h>
 2 const double eps = 1e-6;
 3 int main()
 4 {
 5     int n;
 6     double sum = 0.0;
 7     while(scanf("%d",&n) != EOF)
 8     {
 9         sum = 0.0;
10         if(n == 0)
11         break;
12         if(n <= 4)
13         {
14             sum    = 10.0;    
15         }else
16         if(n > 4&&n <= 8)
17         {
18             sum = 10 + 2 * (n - 4);
19         }else
20         if(n > 8)
21         {
22             while(n > 8)
23             {
24                 sum += 18 ;
25                 n -= 8;
26             }
27             if(n <= 4)
28             {
29                 sum += 2.4 * n;
30             }else
31             {
32                 sum += 10 + (n - 4) * 2;
33             }
34         }
35         int temp = (int)sum;
36         if(sum - temp < eps)
37         {
38             printf("%d\n",temp);
39         }else
40         printf("%.1lf\n",sum);
41     }
42     return 0;
43 }