#include <stdio.h>

#define MAXC 300

short int d[2][MAXC+1];

inline void add(short int a[], short int b[]){
    int tr=0, i=1;
    while((i<=b[0])||(tr>0)){
        tr+=a[i]+b[i];
        a[i]=tr%10;
        tr/=10;
        i++;
    }
    i--;
    if(i>a[0]) a[0]=i;
}

int main(){
    int n;
    freopen("nunta.in", "r", stdin);
    freopen("nunta.out", "w", stdout);
    scanf("%d", &n);
    d[0][0]=d[0][1]=1;
    d[1][0]=d[1][1]=1;
    for(int i=2; i<=n; i++)
        add(d[i&1], d[1-(i&1)]);
    for(int i=d[n&1][0]; i>0; i--)
        fputc(d[n&1][i]+'0', stdout);
    fputc('\n', stdout);
    return 0;
}