Sereja is interested in intervals of numbers, so he has prepared a problem about intervals for you. An interval of numbers is a pair of integers [l, r] (1 ≤ l ≤ r ≤ m). Interval [l₁, r₁] belongs to interval [l₂, r₂] if the following condition is met: l₂ ≤ l₁ ≤ r₁ ≤ r₂.

Sereja wants to write out a sequence of n intervals [l₁, r₁], [l₂, r₂], ..., [l_n, r_n] on a piece of paper. At that, no interval in the sequence can belong to some other interval of the sequence. Also, Sereja loves number x very much and he wants some (at least one) interval in the sequence to have l_i = x. Sereja wonders, how many distinct ways to write such intervals are there?

Help Sereja and find the required number of ways modulo 1000000007 (10⁹ + 7).

Two ways are considered distinct if there is such j (1 ≤ j ≤ n), that the j-th intervals in two corresponding sequences are not equal.

The first line contains integers n, m, x (1 ≤ n·m ≤ 100000, 1 ≤ x ≤ m) — the number of segments in the sequence, the constraints on the numbers in segments and Sereja's favourite number.

In a single line print the answer modulo 1000000007 (10⁹ + 7).