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

typedef long long ll;
typedef double dl;
#define gcd __gcd
#define endl "\n"
#define optimize() ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define fraction() cout.unsetf(ios::floatfield); cout.precision(10); cout.setf(ios::fixed,ios::floatfield);
#define mem(a,b) memset(a,b,sizeof(a))

int main()
{
    optimize();
    ll a,b,c,d,e,f; cin>>a;
    b=a/500;
    c=a%500;
    d= c/5;
    cout<<(b*1000)+(d*5)<<endl;

}