use proconio::input;

fn main() {
    input! {
        (n, a, b): (i64, i64, i64),
    }

    let lcm = a * b / gcd(a, b);
    let ans = n + n / lcm - (n / a + n / b);
    println!("{}", ans);
}

pub fn gcd(a: i64, b: i64) -> i64 {
    let mut a = a.abs();
    let mut b = b.abs();

    while b != 0 {
        let r = a % b;
        a = b;
        b = r;
    }

    a
}