#include <iostream>
#include <vector>
using namespace std;
int main() {
    int n,sum=0;
    cin >> n;
    vector<vector<int>> triangle(n);
    for (int i = 0; i < n; ++i) {
        triangle[i].resize(i + 1);
        triangle[i][0] = 1;
        triangle[i][i] = 1;
        for (int j = 1; j < i; ++j) {
            triangle[i][j] = triangle[i - 1][j - 1] + triangle[i - 1][j];
        }
    }
    for (int i = 0; i < n; ++i) {
        
        for (int j = 0; j <= i; ++j) {
            if(triangle[i][j]%2==0){
                sum++;
            }
        }
    }
    cout<<sum;
    return 0; 
}