from sys import stdin
##  input functions for me
def ria(sep = ''):
    if sep == '' :
        return list(map(int, input().split())) 
    else: return list(map(int, input().split(sep)))
def rsa(sep = ''):
    if sep == '' :
        return input().split() 
    else: return input().split(sep)
def ri(): return int(input())
def rd(): return float(input())
def rs(): return input()
##

def gcd(a, b):
    return b if a == 0 else gcd(b % a, a)

## main ##
t, a, b = map(int, input().split())
lcm = a * b // gcd(a, b)

ca = (t + a - 1) // a
cb = (t + b - 1) // b
cc = (t + lcm - 1) // lcm
print((ca + cb - cc))