N,A,B=(int(x) for x in input().split())
ans=N-N//A-N//B
if A <= B:
  A,B=B,A
k = A
i=1
K=True
while True:
  if k%B==0:
    break
  else:
    i += 1
    k = A*i
  
  if k > N:
    K=False
    break
print(ans+N//k)