#include<bits/stdc++.h>
#include<iostream>
using namespace std;
using LL = long long;
using P = pair<int,int>;
using Graph = vector<vector<int>>;
const long long LINF = 1LL << 60;
#define all(x) (x).begin(), (x).end()
#define rep(i,n) for(int i = 0; i < (n); ++i)
template<class T>void chmin(T&a, T b){if(a > b) a = b;}
template<class T>void chmax(T&a, T b){if(a < b) a = b;}

int main(){
  LL N; 
  cin >> N;

  vector<LL> dp(N+1, LINF);

  dp[0] = 0; dp[1] = 0;

  for(int i = 1; i <= N; ++i){
    for(int j = 2; j <= N; ++j){
      if(i*j>N) break;
      chmin(dp[i*j], dp[i] + j);
    }
  }
  cout << dp[N] << endl;
}