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.

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

-----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.

-----Sample Input-----
5 7 4

-----Sample Output-----
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.

见题面

见题面