#include <bits/stdc++.h>
using namespace std;
int main() 
{
    int n; cin>>n;
    int sum=0;
    if(n >= 500)
    {
        sum = sum + (n/500)*1000;
        n = n - (n/500)*500;
        if(n < 500)
        {
            sum = sum + (n/5)*5;
        }
    }
    else 
    {
        sum = sum + (n/5)*5;
    }
    cout<<sum<<endl;
}