#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define ALL(v) v.begin(),v.end()
typedef long long ll;

#include<bits/stdc++.h>
using namespace std;

const ll INF=1e18;

int main(){
  ll n;
  cin>>n;
  
  if(n==1){
    cout<<2<<endl;
    return 0;
  }
  if(n==2){
    cout<<3<<endl;
    return 0;
  }
  
  set<ll> s;
  for(ll i=1;i*i<=n;i++){
    if(n%i==0){
      s.insert(i);
      s.insert(n/i);
    }
  }
  
  ll ans=INF;
  for(auto x:s){
    if(n/x-1<=x) continue;
    ans=min(ans,n/x-1);
  }
  
  for(ll p=2;p<1000010;p++){
    ll q=p*p;
    ll sum=1+p;
    rep(i,40){
      sum+=q;
      if(sum>n) break;
      if(n%sum==0 && n/sum<p && n/sum>0){
        cout<<min(ans,p)<<endl;
        return 0;
      }
      q*=p;
    }
  }
  if(ans!=INF) cout<<ans<<endl;
  else cout<<n-1<<endl;

  return 0;
}