#include <bits/stdc++.h>
#define pb push_back
#define pf push_front
#define pi 2*acos(0.0)
#define f first
#define s second
#define inf INT_MAX
#define MXN 500001
#define endl "\n"
#define eps 1e-6
#define mod 1000000007
#define all(x) x.begin(), x.end()
#define rev(x) x.rbegin(), x.rend()
#define spc(x) cout << fixed << setprecision(x)
#define fastio {ios_base::sync_with_stdio(false); cin.tie(NULL);}
#define test ll t; cin >> t; while (t--)

typedef long long ll;
using namespace std;

void solve()
{
    ll n; cin>>n;

    ll ans = (n/500)*1000 + ((n%500)/5)*5;
      cout<<ans<<endl;
}
int32_t main()
{
   fastio
   int t = 1;
   //cin >> t;
   while (t--) {
      solve();
   }
   return 0;
}