let me think
A phrase used to indicate that one is trying to think of or remember something or to look for some information. A: "When can I come in for an appointment?" B: "Let me think. There's an opening at 3 o'clock tomorrow, if that works for you."
ˌlet me ˈsee/ˈthink
used when you are thinking or trying to remember something: Now let me see — where did he say he lived?