#include <bits/stdc++.h>

using namespace std;
#define rep(i,n) for (int i = 0; i < (int)(n); ++i)
#define rrep(i,n) for (int i = (int)(n-1); i >= 0; --i)
#define Rep(i,a,b) for (int i = a; i < b; ++i)
#define rRep(i,a,b) for (int i = a; i > b; --i)
#define fore(i,a) for(auto &i:a)
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
#define Bit(x,i) (((x)>>(i))&1)
using ll = long long;
using vi = vector<int>;
using vll = vector<long long>;
using vvi = vector<vi>;
using vvll = vector<vll>;
using vb = vector<bool>;
using vs = vector<string>;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
struct settings{settings(){ios_base::sync_with_stdio(0); cin.tie(0); cout<<fixed<<setprecision(15);};}settingss;
const double PI = acos(-1);
const int INF = 1001001001;
const ll LINF = 1001001001001001001LL;

int main() {
  ll N; cin >> N;
  if(N <= 2) {
    cout << N+1 << endl;
    return 0;
  }
  Rep(b, 2, 1000002) {
    ll base = b;
    while(base < N) base *= b;
    base--;
    base /= b-1;
    if(N%base == 0) {
      cout << b << endl;
      return 0;
    }
  }
  ll ans = N+1;
  for(ll i = 2; i*i <= N; ++i) {
    if(N%i == 0) {
      chmin(ans, max(i, N/i)-1);
    }
  }
  cout << ans << endl;
}