fn main() {
    let mut d = String::new();
    std::io::stdin().read_line(&mut d).ok();
    let d: usize = d.trim().parse().unwrap();
    let mut ab = String::new();
    std::io::stdin().read_line(&mut ab).ok();
    let ab: Vec<usize> = ab.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
    let a = ab[0];
    let b = ab[1];

    let mut result = 1usize << 60;
    for i in 0..=d {
        result = result.min(a*i + (d-i)*b);
    }
    println!("{}", result);
}