#include <bits/stdc++.h>   using namespace std;   const int maxn = 100000 + 10;   int main() {     long long n;     cin >> n;     if (n % 2 == 0) {       cout << 1ll * n / 2;       return 0;     }     bool flag = true;     for (int i = 3; i <= sqrt(n); i += 2) {       if (n % i == 0) {         cout << 1ll * (n - i) / 2 + 1;         return 0;       }     }     cout <<  1 ;     return 0;   }   