#include<bits/stdc++.h>
#define ll long long
#define ull unsigned long long
#define f first 
#define s second 
using namespace std;

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    ll n;
    cin >> n;
    ll cur = (n / 500) * 1000;
    ll r = ((n - (n / 500 * 500)) / 5) * 5;
    cout << (cur + r);
}