#[macro_export]
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        input_rec!{ iter, $($r)* }
    };
    ($($r:tt)*) => {
        let s = {
            use std::io::Read;
            let mut s = String::new();
            std::io::stdin().read_to_string(&mut s).unwrap();
            s
        };
        let mut iter = s.split_whitespace();
        input_rec!{ iter, $($r)* }
    };
}

#[macro_export]
macro_rules! input_rec {
    ($iter:expr) => {};
    ($iter:expr, ) => {};
    ($iter:expr, $var:ident : $t:tt, $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_rec! { $iter, $($r)* }
    };
}

#[macro_export]
macro_rules! read_value {

    // tuple
    ($iter:expr, ( $($t:tt), * )) => {
        ( $(read_value!($iter, $t)), * )
    };

    // array
    ($iter:expr, [ $t:tt; given ]) => {
        (0..(read_value!($iter, usize))).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };
    
    // array
    ($iter:expr, [ $t:tt; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };
    
    // string
    ($iter:expr, chars) => {
        read_value!($iter, String).chars(),collect::<Vec<char>>()
    };
    
    // any other
    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}

fn gcd(a: u64, b: u64) -> u64 {
    if b == 0 { a }
    else { gcd(b, a % b) }
}

fn main() {
    input! {
        t: u64,
        a: u64,
        b: u64,
    }
    let t = t - 1;
    let g = gcd(a, b);
    let at = t / a;
    let ag = b / g;
    let bt = t / b;
    println!("{}", at - (at / ag) + bt + 1);
}