#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> VI;
#define REP(i, n) for(int(i)=0;(i)<(n);++(i))
#define in(T,V) T V;cin>>V;
const int MOD = int(1e9+7);

vector<ll> divis_list(ll num){
    vector<ll> dl;
    ll rt = ll(sqrt((double)num));
    for(ll i = 1; i <= rt; i++){
        if(num % i == 0){
            dl.push_back(i);
            if(num / i != i) dl.push_back(num / i);
        }
    }
    return dl;
}

int main(){
    in(ll,N);
    ll s = N*(N-1)/2;
    ll res = 0;
    auto dl = divis_list(N);
    for(auto i : dl){
        if(N % i == 0 && s % i == 0){
            res = max(res, i);
        }
    }
    cout << res << endl;
}