#include<stdio.h>
#include<string.h>
char one[]="1";
int p,i,a1,b1,max,j,t,k;
char a[225],b[225],c[225]; 
int main ()
{
    freopen("nunta.in","r",stdin);
    freopen("nunta.out","w",stdout);
    scanf("%d",&p);
    strcpy(a,one);
    strcpy(b,one);
    for (j=3; j<=p+2; j++)
    {
        a1=strlen(a)-1;
    b1=strlen(b)-1;
    if(a1<b1)
    max=b1;
    else
    max=a1;
    for(i=max;i>=0;--i)
    {
        c[i]=0;
        if(a1>-1)
        {
            c[i]+=a[a1];
            ++k;
        }
        if(b1>-1)
        {
            ++k;
            c[i]+=b[b1];
        }
        --a1;
        --b1;
        if(k==2)
        c[i]-=48;
        k=0;
        c[i]+=t;
        t=0;
        if(c[i]>57)
        {
            t=c[i]-57;
            c[i]-=10;
        }
    }
    if(t!=0)
    {
        strcpy(c+1,c);
        c[0]=t+48;
    }
        strcpy(a,b);
        strcpy(b,c);
    }
    printf("%s",a);
    return 0;
}