#include using namespace std; // 基本テンプレート struct cww{cww(){ios::sync_with_stdio(false);cin.tie(0);}}star; #define P(x) cout << (x) << endl #define p(x) cout << (x) #define ALL(c) (c).begin(), (c).end() #define RALL(c) (c).rbegin(), (c).rend() #define MAT(type, c, m, n) vector> c(m, vector(n));for(auto& r:c)for(auto& i:r)cin>>i; #define VV(type, c, m, n, i) vector> c(m, vector(n, i)); #define REP(i,a,n) for(int i=(a), i##_len=(n); in; --i) #define perm(c) sort(ALL(c));for(bool c##p=1;c##p;c##p=next_permutation(ALL(c))) #define cauto const auto& #define UNIQUE(v) v.erase( unique(ALL(v)), v.end() ); #define len(x) ((int)(x).size()) #define GET_ARRAY_SIZE(a) (sizeof(a)/sizeof(a[0])) // 型 typedef long long ll; typedef unsigned long long ull; typedef pair pii; typedef pair pss; typedef pair psi; typedef pair pis; typedef vector vi; typedef vector vd; typedef vector vll; typedef vector vs; // 4近傍 //int dy[]={0, 1, 0, -1}; //int dx[]={1, 0, -1, 0}; // 8近傍 //int dy[]={0,0,1,-1,1,1,-1,-1}; //int dx[]={1,-1,0,0,1,-1,1,-1}; //constexpr int dx[]={-2, -2, -1, -1, 1, 1, 2, 2}; //constexpr int dy[]={-1, 1, -2, 2, -2, 2, -1, 1}; ll mod = (int)1e9 + 7; // 定数 #define PI acos(-1.0) constexpr int EPS = (1e-9); constexpr int INF = 100000000; int main() { // cout << setprecision(2) << fixed; ll n; cin >> n; for (ll i = 3; i * i <= n; ++i) { if (n % i == 0) { P(i); return 0; } } P((n % 2 == 0 && n != 4) ? n / 2 : n); return 0; }