#pragma GCC optimize("O3")
#include <bits/stdc++.h>
#define ll long long
#define rep(i,n) for(ll i=0;i<(n);i++)
#define pll pair<ll,ll>
#define pii pair<int,int>
#define pq priority_queue
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define endl '\n'
#define ios ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0);
#define lb(c,x) distance(c.begin(),lower_bound(all(c),x))
#define ub(c,x) distance(c.begin(),upper_bound(all(c),x))

using namespace std;

inline int topbit(unsigned long long x){
	return x?63-__builtin_clzll(x):-1;
}

inline int popcount(unsigned long long x){
	return __builtin_popcountll(x);
}

inline int parity(unsigned long long x){//popcount%2
	return __builtin_parity(x);
}



template<class T> inline bool chmax(T& a,T b){if(a<b){a=b;return 1;}return 0;}
template<class T> inline bool chmin(T& a,T b){if(a>b){a=b;return 1;}return 0;}

const ll INF=1e9+7;

int main(){
    ll n;
    cin >> n;
    if(n==1){
        cout << 2 << endl;
        return 0;
    }
    if(n==2){
        cout << 3 << endl;
        return 0;
    }
    for(ll p=2;p<=min(1000000LL,n);p++){
        vector<ll> b;
        b.push_back(1);
        ll val=p;
        ll s=n;
        while(val<=n){
            b.push_back(val);
            val*=p;
        }
        reverse(b.begin(),b.end());
        ll sz=b.size();
        ll r=0;
        bool ok=true;
        rep(i,sz){
            if(i){
                if(r!=s/b[i]){
                    ok=false;
                    break;
                }
                else{
                    s-=r*b[i];
                }
            }
            else{
                r=s/b[i];
                s-=r*b[i];
            }
        }
        if(ok){
            cout << p << endl;
            return 0;
        }
    }
    vector<ll> q;
    for(ll i=1;i*i<=n;i++){
        if(n%i==0){
            q.push_back(i);
            if(i*i!=n){
                q.push_back(n/i);
            }
        }
    }
    sort(q.rbegin(),q.rend());
    for(auto a:q){
        ll x=n/a-1;
        if(a<x){
            cout << x << endl;
            return 0;
        }
    }
    cout << n-1 << endl;
    return 0;
}