#define _GLIBCXX_FILESYSTEM
#include<bits/stdc++.h>
using namespace std;
#define ll long long

void solve() {
    ll n;
    cin >> n;
    ll ans = n / 500 * 1000;
    n %= 500;
    ans += n / 5 * 5;
    cout << ans << '\n';
    return;
}

int32_t main() {
    ios_base::sync_with_stdio(false);cin.tie(NULL);
    int tc = 1;
    // cin >> tc;
    for(int kase = 1; kase <= tc; kase++) {
        //cout << "Case " << kase << ": ";
        solve();
    }
    return 0;
}