#include <iostream>
#include<conio.h>
#include <stdint.h>
using namespace std;
int main(void)
{
	uint64_t d = 1, z = 0, f = 0, n = 0;
	for(double i=0; i<4000000; ++i)
	{
		z = f+d;
		f = d;
		d = z;
		if(z>4000000)
			break;
		n += z;
	}
	cout << n;
	getch();                             //precaution for blinking screen
	return 0;
}