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

#define endl '\n'
#ifdef LOCAL
    #include "debug.h"    
#else
    #define print(...)
    #define printt(...)
#endif

#define int long long

void run(){
    
    int n;
    cin >> n;

    int ans = (n / 500) * 1000;
    n %= 500;

    ans += (n / 5) * 5;

    cout << ans << endl;
}

int32_t main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    int t = 1;
    // cin >> t;
    
    while( t --> 0 ) 
        run();
    
    return 0;
}