#include<bits/stdc++.h> using namespace std; int main() { int x,n = 0,a = 1; cin>>x; for (int i;i <= x;i++) { n = 1; for (int j = 1;j <= i;j++) { n *= j; } if (i % 2 == 0) { a -= n; } else { a += n; } } cout<<a;