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 l 1 , r 1 belongs to interval l 2 , r 2 if the following condition is met: l 2 ≤ l 1 ≤ r 1 ≤ r 2 . Sereja wants to write out a sequence of n intervals l 1 , r 1 , l 2 , r 2 , ... , 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 (10 9 + 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 (10 9 + 7) . In third example next sequences will be correct: {1, 1, 3, 3} , {1, 2, 3, 3} , {2, 2, 3, 3} , {3, 3, 1, 1} , {3, 3, 2, 2} , {3, 3, 1, 2} .