#include <iostream>
using namespace std;
int f(int x) {
    int s=0;
    int Y=x/2;
    for (int y=1;y<=Y;y++){
        s=s+f(y);
    }
    return 1+s;
}
int main(){
    int n;
    cin>>n;
    int X=n/2;  
    int t=0;
    for (int x=1;x<=X;x++) {
        t=t+f(x);
    }
    cout<<t<<endl;}
/**************************************************************
	Problem: 1307
	User: panyuchen
	Language: C++
	Result: Accepted
	Time:11 ms
	Memory:2072 kb
****************************************************************/