#include<stdio.h>
#include<string.h>
char a[22],b[22],c[22],i,n,t;
int main() {
    freopen("nunta.in","r",stdin),freopen("nunta.out","w",stdout),scanf("%d",&n),a[1]=b[1]=c[1]=a[0]=b[0]=c[0]=1;
    for(;n>1;n--) {
        memset(a,0,sizeof(a));
        for(t=0,i=1;i<=b[0]||i<=c[0]||t;i++,t/=10)
            a[i]=(t+=b[i]+c[i])%10;
        a[0]=i-1,memcpy(c,b,sizeof(b)),memcpy(b,a,sizeof(a));
    }
    for(i=a[0];i;i--)
        printf("%d",a[i]);
}