ltsunpun

Initially I think it is an Artic Warbler, but I hestitate due to its leg is black in colour and Artic Warbler's appearance is rare in Spring per books.
Then I turn to think that it may be a two barred greenish warbler, according to book, its usual appearance should be during period from Sept to next year Apr, but the second wing bar is not so obvious.
Could other experience birders to help?