The intro of Bon Jovi's Thorn in my Side is the same as part of what Iron Maiden song?

The intro of Thorn in my Side off The Circle album is the same as a part of an Iron Maiden song (but not the intro of one) and every time I hear the Bon Jovi song it really bugs me because I can't think of the Iron Maiden song. Can someone please tell me what song it is I'm thinking of?