from collections import Counter, deque, defaultdict
from heapq import heapify, heappop, heappush, nlargest, nsmallest
from bisect import bisect_left, bisect, bisect_right
from copy import deepcopy
from time import perf_counter
import sys
from typing import Any, List, Callable


def debug(*args, sep=" ", end="\n") -> None:
    print(*args, sep=sep, end=end, file=sys.stderr)


def gcd(a, b):
    a = abs(a); b = abs(b)
    if a < b: a, b = b, a
    while b > 0:
        a, b = b, a % b
    return a


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


def main():
    global inf, MOD
    input = sys.stdin.read().split()
    ptr = 0
    inf = float("inf")
    MOD = 998244353

    n, a, b = map(int, input[ptr:ptr + 3]); ptr += 3
    l = lcm(a, b)
    debug(a, b, l)
    ans = n - (n // a + n // b - (n // l))
    print(ans)


if __name__ == "__main__":
    main()