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

using ll = long long;
#define fi first
#define se second

bool check(ll n,ll i){
  ll t=-1;
  int flag=1;
  while(n>0){
    if(t!=-1&&t!=n%i){
      flag=0;
    }
    t=n%i;
    n/=i;
  }
  if(flag==1){
    return true;
  }
  else{
    return false;
  }
}

int main(){
  ll n;
  cin>>n;
  if(n<=2){
    cout<<2<<endl;
  }
  for(ll i=2;i*i<=n;i++){
    if(check(n,i)==true){
      cout<<i<<endl;
      return 0;
    }
  }
  cout<<n-1<<endl;
}