fn gcd(a: u128, b: u128) -> u128 {
    if b == 0 {a} else {gcd(b, a % b)}
}

fn run() {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).unwrap();
    let mut it = s.trim().split_whitespace();
    let t: u128 = it.next().unwrap().parse().unwrap();
    let a: u128 = it.next().unwrap().parse().unwrap();
    let b: u128 = it.next().unwrap().parse().unwrap();
    let c = a * b / gcd(a, b);
    let ans = (t + a - 1) / a + (t + b - 1) / b - (t + c - 1) / c;
    println!("{}", ans);
}

fn main() {
    run();
}