#include <stdio.h>
#include <iostream>
using namespace std;

int n, a[300], b[300], c[300];

void add(int A[], int B[])
{
  int i, t = 0;
  for (i=1; i<=A[0] || i<=B[0] || t; i++, t/=10)
      A[i] = (t += A[i] + B[i]) % 10; 
  
  A[0]= i - 1;
}


int main()
{
	freopen("nunta.in","r",stdin);
	freopen("nunta.out","w",stdout);
	scanf("%d",&n);

	a[0] = a[1] = b[0] = b[1] = 1;

	int i;
	for (i = 3; i <= n + 1; i++)
	{
		add(a,b);
		memcpy(c,b,sizeof(b));
		memcpy(b,a,sizeof(a));
		memcpy(a,c,sizeof(c));
	}

	for (i = b[0]; i >= 1; i--)
		printf("%d",b[i]);
	printf("\n");
	return 0;
}