#include<fstream>
#include<iostream>
using namespace std;
unsigned long a[3][3];


unsigned long p[3][3];


void inmultire(unsigned long p[3][3], unsigned long a[3][3])
{
    unsigned long x[3][3];
    x[0][0] = x[0][1] = x[0][2] = x[1][0] = x[2][0] = 0;

    x[1][1] = p[1][1] * a[1][1] + p[1][2] * a[2][1];
    x[1][2] = p[1][1] * a[1][2] + p[1][2] * a[2][2];
    x[2][1] = p[2][1] * a[1][1] + p[2][2] * a[2][1];
    x[2][2] = p[2][1] * a[1][2] + p[2][2] * a[2][2];

    for(unsigned long i=0;i<=3;i++)
        for(unsigned long j=0;j<=3;j++)
        p[i][j] = x[i][j];
}

void putereLogaritmic(int n)
{

    while(n>0)
    {
        if(n%2 == 1)
        {
            inmultire(p,a);

            n--;
        }
        inmultire(a, a);
        n/=2;
    }
}
int main()
{
    int k;
    a[1][1] = 0;
    a[1][2] = 1;
    a[2][1] = 1;
    a[2][2] = 1;

    p[1][1] = 1;
    p[1][2] = 0;
    p[2][1] = 0;
    p[2][2] = 1;
    ifstream f("kfib.in");
    ofstream g("kfib.out");

    f>>k;

    putereLogaritmic(k-1);
    /*
    for(int i=1;i<=2;i++)
    {
        for(int j=1;j<=2;j++)
            cout<<p[i][j]<<" ";
        cout<<endl;
    }*/
    g<<p[2][2];



}