B"The Little Elephant loves sortings. He has an array a consisting of n integers. Let's number the array elements from 1 to n, then the i-th element will be denoted as ai. The Little Elephant can make one move to choose an arbitrary pair of integers l and r (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89l xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89r xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89n) and increase ai by 1 for all i such that l xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89i xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89r. Help the Little Elephant find the minimum number of moves he needs to convert array a to an arbitrary array sorted in the non-decreasing order. Array a, consisting of n elements, is sorted in the non-decreasing order if for any i (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89i xe2 x80 x89< xe2 x80 x89n) ai xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89ai xe2 x80 x89+ xe2 x80 x891 holds. The first line contains a single integer n (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89n xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89105) -- the size of array a. The next line contains n integers, separated by single spaces -- array a (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89ai xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89109). The array elements are listed in the line in the order of their index's increasing. In a single line print a single integer -- the answer to the problem. Please, do not use the %lld specifier to read or write 64-bit integers in xd0 xa1++. It is preferred to use the cin, cout streams or the %I64d specifier. In the first sample the array is already sorted in the non-decreasing order, so the answer is 0. In the second sample you need to perform two operations: first increase numbers from second to third (after that the array will be: [3, 3, 2]), and second increase only the last element (the array will be: [3, 3, 3]). In the third sample you should make at least 6 steps. The possible sequence of the operations is: (2; 3), (2; 3), (2; 3), (3; 3), (3; 3), (3; 3). After that the array converts to [7, 7, 7, 47]."...