#include<stdio.h>
int main()
{
    int n;
    double p=1,q=2,sum=0;
    scanf("%d",&n);
    for(int i=1;i<=n;i++)
    {
        if(i!=1)
        {
            int a=q;
            q=q+p;
            p=a;
        }
        sum+=q/p;
    }
    printf("%.4lf",sum);
    return 0;
}
```


```

#include <stdio.h>
int main()
{
	int n=0;
    scanf("%d",&n);
    double q[30]={0};
    q[1]=2.0;
    double p[30]={0};
     p[1]=1.0;
    double sum=0;

    for (int i=1;i<=n;i++){
        sum=sum+q[i]/p[i];
        q[i+1]=q[i]+p[i];
        p[i+1]=q[i];
    }
    printf("%.4lf",sum);
    return 0;
}

#include <stdio.h>

int main()
{
    int n, p = 1, q = 2, temp;
    scanf("%d", &n);
    double sum = 0.0;
    for (int i = 0; i < n; i++)
    {
        sum += 1.0 * q / p;
        temp = q;
        q += p;
        p = temp;
    }
    printf("%.4f", sum);
    return 0;
}