#include <iostream>
using namespace std;

long long gcd(int x,long long y){
   if((x == 0) || (y == 0)) return 0;
   while(x != y){
      if(x > y) x -= y;
      else y -= x;
   }
   return x;
}

int main(){
   int n;
   cin >> n;
   cout << gcd(n,(n - 1) * n / 2) << endl;
}