#include <cstdio>
#include <vector>
using namespace std;

const int N = 1000;
const int B = 10;

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

int n;
int d[3][N];

int main() {
	freopen("nunta.in","rt",stdin);
	freopen("nunta.out","wt",stdout);
	scanf("%d",&n);
	d[0][0] = 1; d[0][1] = 0;
	d[1][0] = 1; d[1][1] = 1;
	for (int i = 2; i <= n+1; ++i) add(d[(i-2)%3],d[(i-1)%3],d[i%3]);
	for (int i = d[(n+1)%3][0]; i > 0; --i) printf("%d",d[(n+1)%3][i]);
	printf("\n");
	return 0;
}