#include<stdio.h>
int Fibon1(int n)
{
	if (n == 1 || n == 2)
	{
		return 1;
	}
	else
	{
		return Fibon1(n - 1) + Fibon1(n - 2);
	}
}
int main()
{
	int n = 0;
	int ret = 0;
	scanf("%d", &n);
	ret = Fibon1(n);
	printf("ret=%d", ret);
	return 0;
}

int Fibno2(int n)
{
	int num1 = 1;
	int num2 = 1;
	int tmp = 0;
	int i = 0;
	if (n < 3)
	{
		return 1;
	}
	else
	{
		for (i = 0; i>n-3; i++)
		{
			tmp = num1 + num2;
			num1 = num2;
			num2 = tmp;
		}
		return tmp;
	}
}