#include <bits/stdc++.h> using namespace std; int ans; bool is(const vector<int>& b, int r, int c) { int n = b.size(); for (int i = 0; i < r; ++i) { if (b[i] == c || abs(i - r) == abs(b[i] - c)) { return false; } } return true; } void solve(vector<int>& b, int r) { int n = b.size(); if (r == n) { ans++; return; } for (int c = 0; c < n; ++c) { if (is(b, r, c)) { b[r] = c; solve(b, r + 1); b[r] = -1; } } } void nQ(int n) { vector<int> b(n, -1); solve(b, 0); } int main() { int n; cin >> n; nQ(n); cout<<ans; return 0; }