Three days, max, 500N. The writing's on the wall. But I couldn't take your money, it's just too obvious.
While they're in their a ten-day period of mourning and headless, they're hoping that the world won't be expecting any immediate action. Meanwhile Kim Jong-un is secretly seizing power in Pyongyang and preparing to strike. They've been after the South for decades. He sees this as his big chance.
It will be a dawn raid on 22nd December. So, allowing for the time difference, that would make it 21:17 on 21 Dec in the UK.
Wait and see.
M2