Clockwork Caesar

You intercept a message from a toy radio modem that uses a shifting Caesar cipher.<br/><br/>It rotates by **k = (minute + second) mod 26** at the time it was sent.<br/>Unfortunately, the sender only wrote down the timestamp: `00:02:03`.<br/><br/>Ciphertext:<br/><br/>```<br/>YMNX NX F YJXY TK YMJ HJFXFW<br/>```<br/><br/>Decode the plaintext. The flag is the plaintext, uppercased, with spaces replaced by `_`.<br/>Example format: `CTFBENCH{LIKE_THIS}`<br/>