#include<bits/stdc++.h>
using namespace std;
char v1[105],v2[105],v3[105];
int n,t,i,j;
int main()
{
    freopen("nunta.in","r",stdin);
    freopen("nunta.out","w",stdout);
    scanf("%d",&n);
    n++;
    v1[0]=1;
    v1[1]=1;
    v2[0]=1;
    v2[1]=1;
    if(n==1 || n==2)
    {
        printf("1\n");
        return 0;
    }
    for(int i=3;i<=n;i++)
    {
        memcpy(v3,v1,sizeof(v1));
        //
        t=0;
        for(j=1;j<=v3[0] || j<=v2[0] || t;j++)
        {
            t=t+v3[j]+v2[j];
            v3[j]=t%10;
            t/=10;
        }
        v3[0]=j-1;
        //
        //adunare(v3,v2);
        memcpy(v1,v2,sizeof(v2));
        memcpy(v2,v3,sizeof(v3));
    }
    for(int i=v3[0];i>=1;i--) printf("%d",v3[i]);
    return 0;
}