#include<iostream>
#include<sys/time.h>

using namespace std;

long calc(long n){
	if (n <= 1){
        return n;
    }else{
        return (calc(n - 1) + calc(n - 2));
	}
}
int main(){
    struct timeval tv1, tv2;
    gettimeofday(&tv1, NULL);
	for (int i=0;i<30;i++){
		//cout<<calc(i)<<endl;
        calc(i);
	}
    gettimeofday(&tv2, NULL);
	cout<<"["<<((double)(tv2.tv_sec-tv1.tv_sec)+(double)(tv2.tv_usec-tv1.tv_usec)/1000000)<<"]"<<endl;
	return 0;
}