E. Mod Mod Mod
binary search; dp; math
You are given a sequence of integers a1, a2, ..., an. Let , and for 1 ≤ i < n. Here, denotes the modulus operation. Find the maximum value of f(x, 1) over all nonnegative integers x.
The first line contains a single integer n (1 ≤ n ≤ 200000) — the length of the sequence.The second lines contains n integers a1, a2, ..., an (1 ≤ ai ≤ 1013) — the elements of the sequence.
Output a single integer — the maximum value of f(x, 1) over all nonnegative integers x.
In the first example you can choose, for example, x = 19.In the second example you can choose, for example, x = 3 or x = 2.