#include <cstdio>
#include <algorithm>
#include <cstring>
#define Nmax 212
using namespace std;
int n, i, j, a[Nmax], b[Nmax], c[Nmax];
int main()
{
    freopen("nunta.in", "r", stdin);
    freopen("nunta.out", "w", stdout);
    scanf("%d", &n);
    a[++ a[0]] = 1;
    b[++ b[0]] = 1;
    for (i = 1; i <= n; ++ i)
    {
        memset(c, 0, sizeof(c));
        memcpy(c, a, sizeof(a));
        int j, t = 0;
        for (j = 1; j <= c[0] || j <= b[0] || t; ++ j)
        {
            c[j] = (c[j] + b[j] + t);
            t = c[j] / 10;
            c[j] %= 10;
        }
        c[0] = j - 1;
        memcpy(a, b, sizeof(b));
        memcpy(b, c, sizeof(c));
    }
    for (i = a[0]; i >= 1; -- i)
        printf("%d", a[i]);
    return 0;
}