In the story witches by roald dahl did want to kill all children or just ones in England?

In the story "The Witches" by Roald Dahl, the witches did not want to kill all children, only the ones in England. The Grand High Witch, who was the leader of the witches, had a specific plan to eliminate all the children in England by turning them into mice using a magical formula. She and her coven of witches would lure children into their trap, give them the potion, and then turn them into mice. The witches' goal was to rid England of all children, so that they could live freely and without interference.