#include <stdio.h>
#define N 1000
int t1[N],t2[N],s[N],n;
int Solve()
{
	scanf("%d",&n);
	if (n==1)
		printf("1\n");
	if (n==2)
		printf("2\n");
	if (n>=3)
	{
	t1[N-1]=1;
	t2[N-1]=2;
	for (int i=1; i<=n-2; i++)
	{
		int r=0;
		for (int j=N-1; j>=1; j--)
		{
			s[j]=t1[j]+t2[j]+r;
			r=s[j]/10;
			s[j]=s[j]%10;
		}
		if (i==n-2)
		{
			int j;
			for (j=1; j<=N-1 && s[j]==0; j++);
			int zl=0;
			for (zl=j; zl<=N-1; zl++)
				printf("%d",s[zl]);
			printf("\n");
		}
		for (int j=1; j<=N-1; j++)
		{
			t1[j]=t2[j];
			t2[j]=s[j];
			s[j]=0;
		}
	}
	}
}
int main()
{
	freopen("nunta.in","r",stdin);
	freopen("nunta.out","w",stdout);
	Solve();
}