How many such pairs of letter are there in the word DISTURB each one has as letters between its two them English alphabet?

Here's how to find the pairs of letters in "DISTURB" with letters between them in the alphabet:

* DISTUR**B

We need to find pairs where the letters are not consecutive in the alphabet.

* DI: D and I have one letter between them (E)

* IS: I and S have one letter between them (J, K, L, M, N, O, P, Q, R)

* ST: S and T have one letter between them (U, V, W, X, Y, Z)

* TU: T and U have one letter between them (V)

* UR: U and R have one letter between them (S)

* RB: R and B have one letter between them (S)

There are 6 such pairs in the word "DISTURB".