B'You are given three non-negative integers n , k , and x . Find the maximum possible sum of elements in an array consisting of non-negative integers, which has n elements, its MEX is equal to k , and all its elements do not exceed x . If such an array does not exist, output -1 . The MEX (minimum excluded) of an array is the smallest non-negative integer that does not belong to the array. For instance: The first line contains a single integer t ( 1 <= q t <= q 1000 ) -- the number of test cases. Then follows the description of the test cases. The only line of each test case contains three integers n , k , and x ( 1 <= q n, k, x <= q 200 ). For each test case, output a single number -- the maximum sum of elements in a valid array, or -1 , if such an array does not exist. In the first test case, the maximum sum is 7 , and one of the valid arrays is [0, 1, 2, 2, 2] . In the second test case, there are no valid arrays of length n . In the third test case, the maximum sum is 57 , and one of the valid arrays is [0, 1, 28, 28] . '...