#include<fstream.h>
#include<string.h>
int a[1000],t,b[1000],i,c[1000],n;
int main()
{ifstream q("nunta.in");
ofstream w("nunta.out");
q>>n;
if(n<4)
 w<<n;
else
 {a[0]=1;
 a[1]=1;
 b[0]=1;
 b[1]=2;
 c[0]=1;
 n=n-2;
 while(n!=0)
    {for(i=1;i<=a[0]||i<=b[0]||t;i++,t=t/10)
	   c[i]=(t+=a[i]+b[i])%10;
    c[0]=i-1;
    memcpy(a,b,sizeof(b));
    memcpy(b,c,sizeof(c));
    n--;}}
for(i=c[0];i>=1;i--)
  w<<c[i];
return 0;}