#include <iostream>
long long solve(bool *n_1Ci, int size, int N){
    if(size==N-1){
        int ans=size;
        for(int i=0; i<size; i++){
            if(n_1Ci[i])ans--;
        }
        return ans;
    }
    bool nCi[size+2];
    nCi[0]=1;
    nCi[size+1]=1;
    for(int i=1; i<size; i++){
        nCi[i+1] = n_1Ci[i-1] ^ n_1Ci[i];
    }
    return solve(nCi, size+2, N);
}

int main(void){
    long long N;
    std::cin >> N;
    bool twoCi[1]={1};
    std::cout << solve(twoCi, 1, N) << '\n';
    return 0;
}