#include<stdio.h>

#include<math.h>

int main()

{

    int n,i;

    int f[21]={0,1,1};

    double a=(1.0+sqrt(5.0))/2.0;

    for(i=3;i<=20;i++)//产生前20项

        f[i]=f[i-1]+f[i-2];

    while(scanf("%d",&n)!=EOF)

    {

        if(n<=20)

          printf("%d\n",f[n]);

        else

        {

            double ans=-0.5*log10(5.0)+n*log10(a);

            int answer;

            ans =ans-floor(ans);//取小数部分

            ans=pow(10,ans);//取一次幂

            answer=(int)(ans*1000);//类型转换

            printf("%d\n",answer);

        }

    }

    return 0;

}