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

#define all(a) a.begin(),a.end()
#define el "\n"
#define int long long

// Optimized prime check
bool isprime(int n){
    if(n < 2) return false;
    if(n == 2 || n == 3) return true;
    if(n % 2 == 0 || n % 3 == 0) return false;
    for(int i = 5; i * i <= n; i += 6) {
        if(n % i == 0 || n % (i + 2) == 0) return false;
    }
    return true;
}
void chori_ka_laptop(){
int n; cin>>n;
cout<<(n/500)*1000+((n%500)/5)*5<<endl;
}


int32_t main(){ 
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

#ifndef ONLINE_JUDGE
    freopen("input1.txt", "r", stdin);
    freopen("D://sublime text//output6.txt", "w", stdout);
#endif 

    int t = 1;  
   // cin >> t;
    while(t--) {
        chori_ka_laptop();
    }

    return 0;
}