#include<stdio.h>
#define DIM 1001
int n,a1,b1,a2,b2,m,a[DIM],b[DIM],i,j,t,c[DIM];
int main ()
{
    freopen("nunta.in","r",stdin);
    freopen("nunta.out","w",stdout);
    scanf("%d",&n);
    a1=1;
    b1=1;
    a[1]=1;
    b[1]=1;
    for(i=1;i<=n;++i)
    {
        t=0;
        a2=a1;
        b2=b1;
        if(a1<b1)
        m=b1;
        else
        m=a1;
        for(j=m;j>0;--j)
        {
            c[j]=0;
            if(a2>0)
            c[j]+=a[a2];
            if(b2>0)
            c[j]+=b[b2];
            c[j]+=t;
            --a2;
            --b2;
            t=0;
            t=c[j]/10;
            if(c[j]!=0)
            c[j]=c[j]%10;
        }
        if(t!=0)
        {
            for(j=m+1;j>1;--j)
            c[j]=c[j-1];
            c[1]=t;
            ++m;
        }
        for(j=1;j<=b1;++j)
        a[j]=b[j];
        a1=b1;
        for(j=1;j<=m;++j)
        b[j]=c[j];
        b1=m;
    }
    for(i=1;i<=a1;++i)
    printf("%d",a[i]);
    return 0;
}