#include <bits/stdc++.h>
#define ll long long
#define F first
#define S second
#define endl '\n'
#define Endl '\n'

using namespace std;

const int N = 2e5 + 5;
int tc, n, m, a[N];

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); // cout.tie(0);
    cin >> n;
    ll Ans = (n / 500) * 1000;
    n = n % 500;
    Ans += n / 5 * 5;
    cout << Ans << endl;

    return 0;
}