#!usr/bin/env python3
from collections import defaultdict,deque
from heapq import heappush, heappop
import sys
import math
import bisect
import random
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def I(): return int(sys.stdin.readline())
def LS():return [list(x) for x in sys.stdin.readline().split()]
def S():
    res = list(sys.stdin.readline())
    if res[-1] == "\n":
        return res[:-1]
    return res
def IR(n):
    return [I() for i in range(n)]
def LIR(n):
    return [LI() for i in range(n)]
def SR(n):
    return [S() for i in range(n)]
def LSR(n):
    return [LS() for i in range(n)]

sys.setrecursionlimit(1000000)
mod = 1000000007


#A
def A():
    a,b,c,d,e,f = LI()
    s = pow(a,b,2)+pow(c,d,2)+pow(e,f,2)
    if s&1:
        print(":-(")
    else:
        print(":-)")
    return

#B
def B():
    n = I()
    a = LIR(n)
    ans = []
    q = [deque() for i in range(n)]
    for i in range(n):
        for j in a[i][1:]:
            q[i].append(j)
    f = 1
    while f:
        f = 0
        for i in range(n):
            if q[i]:
                f = 1
                ans.append(q[i].popleft())
    print(*ans)
    return

#C
def C():
    def gcd(a,b):
        if a == 0:
            return b
        return gcd(b%a,a)
    def lcm(a,b):
        return a*b//gcd(a,b)
    t,a,b = LI()
    l = lcm(a,b)
    print((t-1)//a+(t-1)//b-(t-1)//l+1)
    return

#D
def D():

    return

#E
def E():

    return

#F
def F():

    return

#Solve
if __name__ == "__main__":
    C()