import json
import requests
import sys


def main():
    try:
        n = float(sys.argv[1])
    except IndexError:
        sys.exit("Missing command-line argument")
    except (ValueError, TypeError):
        sys.exit("Command-line argument is not a number")
    try:
        response = requests.get("https://api.coindesk.com/v1/bpi/currentprice.json")
        data = response.json()
        conversion_rate = float(data['bpi']['USD']['rate'].replace(',', ''))
    except requests.RequestException:
        pass
    print(f"${n * conversion_rate:,.4f}")



if __name__ == "__main__":
    main()