#include using namespace std; using ll = long long; #define ALL(obj) (obj).begin(),(obj).end() template using priority_queue_reverse = priority_queue,greater>; constexpr long long MOD = 1'000'000'000LL + 7; //' constexpr long long MOD2 = 998244353; constexpr long long HIGHINF = (long long)1e18; constexpr long long LOWINF = (long long)1e15; constexpr long double PI = 3.1415926535897932384626433L; template vector multivector(size_t N,T init){return vector(N,init);} template auto multivector(size_t N,T... t){return vector(N,multivector(t...));} template void corner(bool flg, T hoge) {if (flg) {cout << hoge << endl; exit(0);}} template ostream &operator<<(ostream &o, const map&obj) {o << "{"; for (auto &x : obj) o << " {" << x.first << " : " << x.second << "}" << ","; o << " }"; return o;} template ostream &operator<<(ostream &o, const set&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;} template ostream &operator<<(ostream &o, const multiset&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;} template ostream &operator<<(ostream &o, const vector&obj) {o << "{"; for (int i = 0; i < (int)obj.size(); ++i)o << (i > 0 ? ", " : "") << obj[i]; o << "}"; return o;} template ostream &operator<<(ostream &o, const pair&obj) {o << "{" << obj.first << ", " << obj.second << "}"; return o;} void print(void) {cout << endl;} template void print(Head&& head) {cout << head;print();} template void print(Head&& head, Tail&&... tail) {cout << head << " ";print(forward(tail)...);} template void chmax(T& a, const T b){a=max(a,b);} template void chmin(T& a, const T b){a=min(a,b);} vector split(const string &str, const char delemiter) {vector res;stringstream ss(str);string buffer; while( getline(ss, buffer, delemiter) ) res.push_back(buffer); return res;} int msb(int x) {return x?31-__builtin_clz(x):-1;} void YN(bool flg) {cout << (flg ? "YES" : "NO") << endl;} void Yn(bool flg) {cout << (flg ? "Yes" : "No") << endl;} void yn(bool flg) {cout << (flg ? "yes" : "no") << endl;} /* * @title NBase - N進数 * @docs md/util/NBase.md */ class NBase{ public: inline static vector translate(long long X,long long N) { assert(abs(N)>1); vector res; while(1) { long long b = (X%abs(N)+abs(N)) % abs(N); res.push_back(b); (X -= b) /= N; if(X==0) break; } return res; } //Digit Sum inline static constexpr long long digit_sum(long long N, long long K) { long long sum = 0; for (; N > 0; N /= K) sum += N % K; return sum; } }; //divisor O(sqrt(N)) set Divisor(long long N) { set ret; for (long long i = 1; i*i <= N; ++i) { if (N%i == 0) { ret.insert(i); ret.insert(N / i); } } return ret; } //verify https://atcoder.jp/contests/abc112/tasks/abc112_d /** * @url * @est */ int main() { cin.tie(0);ios::sync_with_stdio(false); ll N; cin >> N; corner(N==1,2); ll ans = N-1; for(ll p=2;p*p<=N;++p) { auto v = NBase::translate(N,p); int flg=1; for(int i=0;i+1=2 && p>(N/p)) chmin(ans,p); } cout << ans << endl; return 0; }