vrum

#include <stdio.h>
int main()
{
     double total = 1, a = 1, b = 1, b2 = 1.5;
     int i = 0, n = 0;
     scanf("%d", &n);
     for (i = 2; i <= n; i++)
     {
          a = a *2; b++;b2 += 1.5;
          if(i % 2 == 0)
          {
               total += a / b2;
          }
          else if(i % 2 != 0)
          {
               total += b / a;
          }
     }
     printf("S: %.2lf", total);
     return 0;
}