from fractions import gcd
from datetime import date, timedelta
from heapq import*
import math
from collections import defaultdict, Counter
import sys
from bisect import *
sys.setrecursionlimit(10 ** 7)
MOD = 10 ** 9 + 7


def lcm(a, b):
    return a * b / gcd(a, b)

def main():
    t, a, b = map(int, input().split())
    aa = t // a
    if t % a != 0:
        aa+=1
    bb = t // b
    if t % b != 0:
        bb+=1
    cc = t // int(lcm(a, b))
    if t % lcm(a,b) != 0:
        cc +=1
    print(aa + bb  - cc)


if __name__ == '__main__':
    main()