#include<bits/stdc++.h>
using namespace std;
#define e4 ios_base::sync_with_stdio(false); cin.tie(NULL)
#define endl '\n'
#define ll  long long
#define test_case int tc;cin>>tc;while(tc--)


int main() {

	
	  e4;

	  ll n,ans=0;

	  cin>>n;

	  ans+=(n/500)*1000;

	  n=n%500;

	  ans+=(n/5)*5;

	  cout<<ans;

}

	
		   //           S m o t h e r e d  M a t e !!		 //