B'The Kingdom of Kremland is a tree (a connected undirected graph without cycles) consisting of n vertices. Each vertex i has its own value a_i . All vertices are connected in series by edges. Formally, for every 1 <= q i < n there is an edge between the vertices of i and i+1 . Denote the function f(l, r) , which takes two integers l and r ( l <= q r ): Your task is to calculate the following sum: sum_{l=1}^{n} sum_{r=l}^{n} f(l, r) The first line contains a single integer n ( 1 <= q n <= q 10^5 ) -- the number of vertices in the tree. The second line contains n integers a_1, a_2, ldots, a_n ( 1 <= q a_i <= q n ) -- the values of the vertices. Print one number -- the answer to the problem. In the first example, the function values xe2 x80 x8b xe2 x80 x8bwill be as follows: In the second example, the function values xe2 x80 x8b xe2 x80 x8bwill be as follows: '...