Chef and Magical Steps

Chef has a new customer and he wants to prepare his order as soon as possible. While preparing, he sees that he is out of mint sauce. He has to run upstairs to get it from other kitchen. Chef is currently on the $X^{th}$ stair. He has to climb all the way up to the $Y^{th}$ stair in minimum number of steps. In one step, Chef can do one of the following things: - Climb a single stair. ( i.e go fr