#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,i,j,nrcif,t,aux;
    fscanf(fin, "%hd", &n);
    if (n == 1)
    {
        fprintf(fout, "%d", 1);
        return 0;
    }
    a[0] = b[0] = 1;
    for (i=1; i<=n-1; i++)
    {
        t = 0;
        for (j=0; j<=nrcif; j++)
        {
            aux = b[j];
            b[j] += a[j]+t;
            if (b[j] >= 10)
            {
                t = 1;
                b[j] -= 10;
            }
            else
                t = 0;
            a[j] = aux;
        }
        if (t != 0)
            b[++nrcif] = t;
    }
    for (i=nrcif; i>=0; i--)
        fprintf(fout, "%d", (int)b[i]);
    return 0;
}