import sys
from math import gcd


def input(): return sys.stdin.readline().rstrip('\n')


def cdiv(a, b):
    return (a + b - 1) // b


def main():
    t, a, b = map(int, input().split())
    c = a * b // gcd(a, b)
    return cdiv(t, a) + cdiv(t, b) - cdiv(t, c)


if __name__ == '__main__':
    ret = main()
    if ret is not None:
        print(ret)