[ ] User can see an input. [ ] User can only enter a number into their input. [ ] User can convert from usd to vnd by pressing a button. [ ] User can convert from vnd to usd by pressing a button. [ ] User can see the converted currency is formatted. [ ] User expects input to automatically be focused on page load. [ ] User can enter a value into an input to convert. [ ] User can choose the from currency [ ] User can choose the to currency [ ] User can click the button to see the converted amount with commas between the numbers in the correct place. [ ] User can see the correct curreny sign.