#include <iostream>
#include <vector>

using namespace std;

bool safe(vector <int> f, int k, int st) {
    int i;
    for (i = 0; i < k; i++) {
        if (f[i] == st || abs(st - f[i]) == k - i) {
            return 0 == 1;
        }
    }
    return 0 == 0;
}

int ferz(vector <int> f, int k, int n) {
    int st;
    st = f[k] + 1;
    if (st == n) {
        if (k == 0) {
            return 0;
        }
        else {
            f[k] = -1;
            return ferz(f, k - 1, n);
        }
    }
    if (safe(f, k, st)) {
        if (k < n - 1) {
            f[k] = st;
            return ferz(f, k + 1, n);
        }
        else {
            f[k]++;
            return 1 + ferz(f, k, n);
        }
    }
    else {
        f[k]++;
        return ferz(f, k, n);
    }
}


int main() {
    int n, i, j;
    cin >> n;
    vector <int> f(0);
    for (i = 0; i < n; i++) {
        f.push_back(-1);
    }
    cout << ferz(f, 0, n);
    return 0;
}