#include<stdio.h>
#define lim 5001
#define len 1050
int fbn[lim][len];
void fibonacci()
{
int i,j,k,sum;
fbn[0][0]=0;
fbn[1][0]=1;
fbn[2][0]=1;
for(i=3;i<lim;i++)
{
for(j=0;j<len;j++)
{
fbn[i][j]=fbn[i][j]+fbn[i-2][j]+fbn[i-1][j];
if(fbn[i][j]>=10)
{
fbn[i][j+1]=fbn[i][j+1]+fbn[i][j]/10;
fbn[i][j]=fbn[i][j]%10;
}
}
}
}
int main()
{
fibonacci();
int n,i,j,k,lenth;
while(scanf("%d",&n)==1)
{
for(i=len-1;i>0;i--)
{
if(fbn[n][i]!=0)break;
}
for(;i>=0;i--)printf("%d",fbn[n][i]);
printf("\n");
}
return 0;
}