#include <stdio.h>
#include <string.h>

#define cmax 256
#define BAZA 10

int n,A[cmax],B[cmax],C[cmax];

void Add()
{
	int i,t=0;
	for(i=1;i<=A[0]||t;++i)
	{
		C[i]+=A[i]+t;
		t=C[i]/BAZA;
		C[i]%=BAZA;
	}
	if(i>C[0]) C[0]=i-1;
}

int main()
{
	freopen("nunta.in","r",stdin);
	freopen("nunta.out","w",stdout);
	B[0]=B[1]=C[0]=C[1]=1;
	scanf("%d",&n);
	int i;
	for(i=2;i<=n;++i)
	{
		memcpy(A,B,sizeof(B));
		memcpy(B,C,sizeof(C));
		Add();
	}
	printf("%d",C[C[0]]);
	for(i=C[0]-1;i;--i)
		printf("%d",C[i]);
	printf("\n");
	return 0;
}