View Code of Problem 71

#include<iostream>

using namespace std;

int main(){
	int n;
	cin>>n;
	double sum=0;
	double temp1=1;
	double temp2=2;
	for(int i=0;i<n;++i){
		sum+=temp2/temp1;
		double temp=temp1;
		temp1=temp2;
		temp2+=temp;
	}
	printf("%.2lf",sum);
	return 0;
}