Formation#2708
Once, an auditor visited military unit No. 192.168.0.9 and observed the formation of its soldiers. He noticed that when the soldiers lined up in rows of columns, the last row had N-1 soldiers, and when the same number of soldiers lined up in rows of columns, the last row had M-1 soldiers. All other rows were full.
Later, he needed to determine the number of soldiers in the unit based on this information. He realized that it is not possible to uniquely determine this number, so he decided to find the minimal possible number of soldiers. This task was delegated to his deputy, that is, to you. Congratulations.
The input file contains two natural numbers and separated by a space (2 \le N,\ M \le 150000).
Output a single number — the minimal possible number of soldiers in the unit. It is guaranteed that this number fits within the range of Longint.
Example 1