#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n;
  cin >> n;
  long long ans = n - 1;
  for (long long i = 2; i * i <= n; ++i) {
    if (n % i == 0) {
      ans = min(ans, i + n / i - 2);
    }
  }
  cout << ans << endl;
  return 0;
}
