#include <bits/stdc++.h>
#include <cmath>
#include <bitset>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update> pbds;
#define ll long long int
#define lld long double
#define yes cout << "Yes" << endl
#define no cout << "No" << endl
#define gcd(a, b) __gcd(a, b)
#define lcm(a, b) ((a * b) / gcd(a, b))
#define pi acos(-1.00)
ll rec(vector<vector<ll>>&a,vector<ll>&v,ll in,ll jn,ll n,ll m){
  if(in==n-1&& a[in][jn]==2){
      return jn;
  }
  if(a[in][jn]==1){
    a[in][jn]=2;
      ll x=rec(a,v,in,jn+1,n,m);
      
      return x;
  }
  if(a[in][jn]==3){
    a[in][jn]=2;
    ll x=rec(a,v,in,jn-1,n,m);
   
    return x;
}
   return rec(a,v,in+1,jn,n,m);
}
void evan(int t)
{
  ll n;cin>>n;
  ll ans=(n/500)*1000;
  n=n%500;
  ans+=(n/5)*5;
  cout<<ans<<"\n";
}
signed main()
{
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(nullptr);
  int t = 1;
  //cin >> t;
  for (int i = 1; i <= t; i++)
  {
    evan(i);
  }
}