#include <bits/stdc++.h>

#define MaxN 215
#define INF 2140000000
#define INFLL 4611686018427387904

using namespace std;

FILE *IN,*OUT;

int N;
unsigned char a[MaxN],b[MaxN];
int main()
{
    IN=fopen("nunta.in","r");
    OUT=fopen("nunta.out","w");

    fscanf(IN,"%d",&N);

    b[0]=b[1]=1;

    for(int i=1;i<=N+1;i++)
    {

        int t=0,lb=b[0],p,l=max(a[0],b[0]);
        for(int i=1;i<=l;i++)
        {
            p=b[i];
            b[i]+=a[i]+t;
            a[i]=p;
            t=b[i]/10;
            b[i]%=10;
            if(i==l&&t>0)
                l++;
        }
        b[0]=l;
        a[0]=lb;
    }
    for(int i=a[0];i>0;i--)
        fprintf(OUT,"%d",a[i]);
    return 0;
}