is an infinite sequence of integers that satisfies to Fibonacci condition F_i + 2 = F_i + 1 + F_i for any integer i. Write a program, which calculates the value of F_n for the given values of F_i and F_j.

The input contains five integers in the following order: i, F_i, j, F_j, n.
−1000 ≤ i, j, n ≤ 1000, i ≠ j,
−2·10⁹ ≤ F_k ≤ 2·10⁹ (k = min(i, j, n), …, max(i, j, n)).

The output consists of a single integer, which is the value of F_n.

In the example you are given: F₃ = 5, F₋₁ = 4; you asked to find the value of F₅. The following Fibonacci sequence can be reconstructed using known values:

Thus, the answer is: F₅ = 12.