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

#define ll long long
#define nl "\n"
#define ws " "
#define FASTIO ios_base::sync_with_stdio(false); cin.tie(NULL);
#define MOD 1000000007

typedef vector<ll> vi;
typedef vector<pair<ll, ll>> vii;

int main () {
    FASTIO
    ll n;
    cin>>n;
    ll ans = 0;
    ll x = n / 500;
    // ll xrem = n % 500;
    ans += x * 1000;
    n %= 500;
    ans += (n / 5) * 5;
    cout<<ans<<nl;
    return 0;
}