Problem Statement

Given are integers A, B, and N.
Find the maximum possible value of floor(Ax/B) - A × floor(x/B) for a non-negative integer x not greater than N.
Here floor(t) denotes the greatest integer not greater than the real number t.

Input

Input is given from Standard Input in the following format:
A B N

Output

Print the maximum possible value of floor(Ax/B) - A × floor(x/B) for a non-negative integer x not greater than N, as an integer.

Constraints

• 1 ≤ A ≤ 10^{6}
• 1 ≤ B ≤ 10^{12}
• 1 ≤ N ≤ 10^{12}
• All values in input are integers.

Sample Input 1

5 7 4

Sample Output 1

2

When x=3, floor(Ax/B)-A×floor(x/B) = floor(15/7) - 5×floor(3/7) = 2. This is the maximum value possible.

Sample Input 2

11 10 9

Sample Output 2

9

见题面 Input 部分

见题面 Output 部分