B"A girl named Sonya is studying in the scientific lyceum of the Kingdom of Kremland. The teacher of computer science (Sonya's favorite subject!) invented a task for her. Given an array a of length n , consisting only of the numbers 0 and 1 , and the number k . Exactly k times the following happens: Sonya's task is to find the probability that after all the operations are completed, the a array will be sorted in non-decreasing order. She turned to you for help. Help Sonya solve this problem. It can be shown that the desired probability is either 0 or it can be represented as dfrac{P}{Q} , where P and Q are coprime integers and Q not equiv 0~ pmod {10^9+7} . The first line contains two integers n and k ( 2 <= q n <= q 100, 1 <= q k <= q 10^9 ) -- the length of the array a and the number of operations. The second line contains n integers a_1, a_2, ldots, a_n ( 0 <= a_i <= 1 ) -- the description of the array a . If the desired probability is 0 , print 0 , otherwise print the value P cdot Q^{-1} pmod {10^9+7} , where P and Q are defined above. In the first example, all possible variants of the final array a , after applying exactly two operations: (0, 1, 0) , (0, 0, 1) , (1, 0, 0) , (1, 0, 0) , (0, 1, 0) , (0, 0, 1) , (0, 0, 1) , (1, 0, 0) , (0, 1, 0) . Therefore, the answer is dfrac{3}{9}= dfrac{1}{3} . In the second example, the array will not be sorted in non-decreasing order after one operation, therefore the answer is 0 . "...