#include <cstdio>
using namespace std;
const int nmax = 1005;
int n, x[2][nmax];

void add(int a[], int b[])
{
    int i, t = 0;
    for(i=1; i<=a[0] || i<=b[0] || t; i++, t /= 10)
        a[i]=(t+=a[i]+b[i])%10;
    a[0]=i-1;
}

int main()
{
    freopen("nunta.in", "r", stdin);
    freopen("nunta.out", "w", stdout);
    scanf("%d", &n);
    x[0][0]=x[0][1]=x[1][0]=x[1][1]=1;
    for(int i=2; i<=n; i++)
        add(x[i&1], x[!(i&1)]);

    for(int i=x[n&1][0]; i>0; i--)
        printf("%d", x[n&1][i]);
    printf("\n");
    fclose(stdin);
    fclose(stdout);
    return 0;
}