View Code of Problem 71

#include<stdio.h>
#include<cstdlib>
#include<cmath>
#include<iostream>
#include<algorithm>
using namespace std;
typedef long long ll;
int main(){
       int n;
       scanf("%d", &n);
       float a=2,b=1;
       if(n==1) printf("%.2f",a/b);
       float k,sum=2.0;
       for(int i=1;i<n;i++){
       	    k=a;
       	    a=a+b;
       	    b=k;
       	    sum+=a/b;
	   }
	   printf("%.2f",sum);
	   	  return 0;
}