#include <cstdio>

using namespace std;

char a[210],b[210];

FILE *fin = fopen ("nunta.in","r");
FILE *fout = fopen ("nunta.out","w");
int main (){


    short n,y;
    short t,nr,k,i;
    fscanf (fin,"%hd",&n);
    if (n <= 2){
        fprintf (fout,"%hd",n);
        return 0;
    }
    // fibonacci

    a[1] = b[1] = 1;
    y = 1;
    for (k=1;k<n;k++){
        t = 0;
        for (i=1;i<=y;i++){
            nr = b[i];
            b[i] += a[i]+t;
            if (b[i] >= 10){
                t = 1;
                b[i] -= 10;
            }
            else
                t = 0;
            a[i] = nr;
        }
        if (t != 0)
            b[++y] = t;

    }
    for (i=y;i>=1;i--)
        fputc (b[i]+'0',fout);
        //fprintf (fout,"%c",b[i]+'0');


    return 0;
}