View Code of Problem 71

#include<stdio.h>

int main(){
    int n;
    double up = 2;
    double down = 1;
    double sum = 0;
    double temp;
    scanf("%d",&n);

    for(int i=0;i<n;i++){
        sum += up/down;
        temp = up;
        up = up + down;
        down = temp;
    }
    printf("%.2f\n",sum);


    return 0;
}