import sys
input=lambda: sys.stdin.readline().rstrip()
t,a,b=map(int,input().split())
def gcd(a,b):
  while b:
    a,b=b,a%b
  return a
m=a*b//gcd(a,b)
print((t-1)//a+(t-1)//b-(t-1)//m+1)