Fibanachi

#include <stdio.h>

int a;
int sum = 0;
int mas[100];


void massive (int i)
{
	if (i <= a)
	{
		mas[0] = 0;
		mas[1] = 1;
		mas[i] = mas[i-1] + mas[i-2];
		massive(i+1);
	}
}

void suma (int i)
{
	mas[0] = 0;
	mas[1] = 1;
	if (i <= a)
	{
		sum += (mas[i-1] + mas[i-2]);
		suma(i+1);
	}
}
int main()
{
	scanf ("%d", &a);
	mas[0] = 0;
	mas[1] = 1;
	sum = mas[0] + mas[1];
	massive(3);
	suma(3);
	if (a == 0)
	{
		printf("%d", a);
	}
	else
	{
		printf("%d", sum);
	}
	return 0;
}