Arithmetic progressions#9895
Let a_n, b_n, c_n be arithmetic progressions. It is known that
a_1 + b_1 + c_1 = p,
a_2 + b_2 + c_2 = q
For the given positive integer find the value of a_k + b_k + c_k.
Three integers p, q~(|p|, |q| \le 10^{18}), k~(k > 0).
Print the value of a_k + b_k + c_k. It is known that output is no more than 10^{18} by absolute value.
Example 1