#include <algorithm>
#include <cmath>
#include <cstdio>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>
using namespace std;
using ll = long long;
int main() {
  ll n;
  cin >> n;
  if(n == 1) {
    cout << 1 << endl;
    return 0;
  }
  cout << n / 2 << endl;
  return 0;
}