t, a, b = map(int, input().split())

#import fractions
import math
from functools import reduce
def lcm_base(x, y):
  #return (x * y) // fractions.gcd(x, y)
  return (x * y) // math.gcd(x, y)

def lcm_list(numbers):
  return reduce(lcm_base, numbers, 1)

l = lcm_base(a, b)
q, r = divmod(t-1, l)
ans = q*(l//a+l//b-1)+r//a+r//b+1
print(ans)