#include <bits/stdc++.h>
using namespace std;

template<class _Tc>class Matrix{private:unsigned int r,c;vector<vector<_Tc>>v;public:unsigned int rows(){return r;}unsigned int columns(){return c;}unsigned int size(){return r*c;}Matrix(unsigned int rows,unsigned int columns):r(rows),c(columns){v.resize(rows);for(unsigned int i=0;i<rows;++i)v[i].resize(columns);}vector<_Tc>&operator[](unsigned int row){return v[row];}const Matrix&operator*=(const Matrix&m){if(c!=m.r)throw;Matrix n(r,m.c);for(unsigned int i=0;i<r;++i)for(unsigned int j=0;j<m.c;++j)for(unsigned int k=0;k<c;++k)n.v[i][j]+=v[i][k]*m.v[k][j];return*this=n;}const Matrix&operator*=(const _Tc &m){for(unsigned int i=0;i<r;++i)for(unsigned int j=0;j<c;++j)v[i][j]*=m;return*this;}static const Matrix unit(unsigned int s,_Tc v=1){Matrix n(s,s);for(unsigned int i=0;i<s;++i)n.v[i][i]=v;return n;}const Matrix pow(unsigned int p)const{if(c!=r)throw;Matrix n=Matrix::unit(r),m=*this;while(p>0){if(p&1)n*=m;m*=m;p>>=1;}return n;}};

long long fib(int n){
    Matrix<long long> a(2,2);
    a[0][0] = a[0][1] = a[1][0] = 1; a[1][1] = 0;
    a = a.pow(n);
    return a[1][0];
}

int main(){
    int n;
    cin >> n;
    cout << fib(n+1) << endl;
    return 0;
}