#include <bits/stdc++.h>
using namespace std;

inline void solve()
{
    int n;
    cin >> n;

    int v = n/500;
    int r = n%500;

    cout << (v*1000 + (r/5) * 5 ) << "\n";
}

int main()
{
    ios::sync_with_stdio(false); cin.tie(nullptr);
    int t = 1;
    //cin >> t;
    for(int i=1; i <= t; ++i) solve();
    return 0;
}