#include<stdio.h>
short n,i,t,c,d;
char a[210],b[210];
int main()
{
    freopen("nunta.in","r",stdin),freopen("nunta.out","w",stdout),scanf("%hd",&n);
    for(c=d=a[1]=b[1]=1;n>1;--n) {
        for(t=0,i=1;i<=c||i<=d||t;++i,t/=10)
            b[i]=(t+=a[i]+b[i])%10;
        for(d=i-1,t=0,i=1;i<=d;++i)
            a[i]=b[i]-(i<=c?a[i]:0)-t,a[i]+=(t=a[i]<0)*10;
        for(c=i-1;c>1&&!a[c];--c);
    }
    for(i=d;i;--i)
        printf("%c",b[i]+'0');
    return 0;
}