Rahul and his lazy friend

Rahul and his friend Saurabh are very lazy person they used their own alarm clock for waking up . both alarm commence ringing together and ring at interval X and Y seconds respectively. Rahul and saurabh wake up in a condition when both alarm Ring together. find the minimum time taken by the alarms so they wake up. Note:- they don’t wake up at the beginning of ringing the alarm. Input - The fir