#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define all(v) v.begin(),v.end()
#define endl '\n'
#pragma GCC target("popcnt")
#define bug(...) __f (#__VA_ARGS__, __VA_ARGS__);
template <typename Arg1>void __f (const char* name, Arg1&& arg1) {cout << name << " : " << arg1 << endl;}template <typename Arg1, typename... Args>void __f (const char* names, Arg1&& arg1, Args&&... args){const char* comma = strchr (names + 1, ',');cout.write (names, comma - names) << " : " << arg1 << " | "; __f (comma + 1, args...);}

void solve(ll cs) {
    ll n;
    cin >> n;
    ll ans = 0;
    while(n>=500){
        n -= 500;
        ans += 1000;
    }
    while(n>=5){
        n -= 5;
        ans += 5;
    }

    cout << ans << endl;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);
  
    ll t=1, cs=1;
    //cin>>t;
    while(t--) {
        solve(cs++);
    }

    return 0;
}