/*指針練習1*/
#include "stdio.h"
main()
{
 float peven(),podd(),dcall();
float sum;
int n;
while(1)
  {
   scanf("%d",&n);
   if(n>1)
   break;
   }
if(n%2==0)
   {
    printf("Even=");
    sum=dcall(peven,n);
     }
 else
     {
      printf("Odd=");
      sum=dcall(podd,n);
       }
 printf("%f",sum);
}

float peven(int n)
{
float s;
int i;
s=1;
for(i=2;i<=n;i+=2)
s+=1/(float)i;
return(s);
}
float podd(n)
int n;
{
float s;
int i;
s=0;
for(i=1;i<=n;i+=2)
s+=1/(float)i;
return(s);
}
float dcall(fp,n)
float (*fp)();
int n;
{
float s;
s=(*fp)(n);
return(s);
}