The k-th Term of an Arithmetic Progression

Problem Description

An arithmetic progression is a sequence in which, starting from the second term, the difference between each term and the previous one equals the same constant. This constant is called the common difference (usually denoted $d$), and the first term is called the first term (usually denoted $x$).

For example: an arithmetic progression with first term $5$ and common difference $2$ is: $5, 7, 9, 11, 13, \dots$. Its 1st term is $5$, its 2nd term is $7$, its 3rd term is $9$, and so on.

Now given the first term $x$ and the common difference $d$ of an arithmetic progression, find the value of its $k$-th term.

Input Format

One line containing three integers $x, d, k$, separated by spaces. $0 < x, d, k < 1000$.

Output Format

Output one integer: the value of the $k$-th term of the arithmetic progression.

Sample Input

5 1 3

Sample Output

7

Sample Explanation

First term $x = 5$, common difference $d = 1$, the sequence is: $5, 6, 7, \dots$. The 3rd term is $5 + (3-1) \times 1 = 7$.

Hint

• Three numbers on one line. The $k$-th term = first term + (number of steps taken) × common difference — from the 1st term to the $k$-th term, how many steps are taken?
• Check against the sample: 5 1 3 → 7.