#include <bits/stdc++.h>

using namespace std;

ifstream fin("nunta.in");
ofstream fout("nunta.out");

const int NMAX = 1002;
short a[NMAX][NMAX];

int main()
{
    int n;
    fin >> n;
    a[1][0]=1;
    a[1][1]=1;
    a[2][0]=1;
    a[2][1]=2;
    a[3][0]=1;
    a[3][1]=3;
    if(n<=3)
    {
        fout << n;
        return 0;
    }
    /// Fibo
    int sz,i,j,r=0;
    for(i=4;i<=n;i++)
    {
        sz=a[i-1][0];
        a[i][0]=a[i-1][0];
        for(j=1;j<=sz;j++)
        {
            a[i][j]=a[i-1][j]+a[i-2][j]+r;
            r=a[i][j]/10;
            a[i][j]%=10;
        }
        if(r!=0)
        {
            a[i][0]++;
            a[i][a[i][0]]=r;
            r=0;
        }
    }
    for(i=a[n][0];i>=1;i--)
        fout << a[n][i];
    return 0;
}