string = input()
bulb, side = string.split()
bulb = int(bulb)
side = int(side)


counter = 0
counter1 = 0
for rotations in range(side+1):
    for index in range(side):
        counter = (bulb + 1) / (side + 1)
    if counter > counter1:
        counter1 = counter
   
print(int(counter1)-1)