【題解】AtCoder ABC160B – Golden Coins

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

string s;
int n, ans;

int main(){
    cin >> n;
    ans = n / 500;
    n -= ans * 500;
    ans *= 1000;
    ans += (n/5) * 5;
    cout << ans << "\n";
}