#include <cstdio>

using namespace std;

char a[209],b[209];

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

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

    a[0] = b[0] = 1;
    y = 0;
    for (k=1;k<n;k++){
        t = 0;
        for (i=0;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>=0;i--)
        fputc (b[i]+'0',fout);


    return 0;
}