#[allow(unused_imports)]
use std::cmp::{max, min};
#[allow(unused_imports)]
use std::collections::{HashMap, HashSet};

mod util {
    use std::io::stdin;
    use std::str::FromStr;
    use std::fmt::Debug;

    #[allow(dead_code)]
    pub fn line() -> String {
        let mut line: String = String::new();
        stdin().read_line(&mut line).unwrap();
        line.trim().to_string()
    }

    #[allow(dead_code)]
    pub fn get<T: FromStr>() -> T
    where
        <T as FromStr>::Err: Debug,
    {
        let mut line: String = String::new();
        stdin().read_line(&mut line).unwrap();
        line.trim().parse().unwrap()
    }

    #[allow(dead_code)]
    pub fn gets<T: FromStr>() -> Vec<T>
    where
        <T as FromStr>::Err: Debug,
    {
        let mut line: String = String::new();
        stdin().read_line(&mut line).unwrap();
        line.split_whitespace()
            .map(|t| t.parse().unwrap())
            .collect()
    }

    #[allow(dead_code)]
    pub fn get2<T: FromStr, U: FromStr>() -> (T, U)
    where
        <T as FromStr>::Err: Debug,
        <U as FromStr>::Err: Debug,
    {
        let mut line: String = String::new();
        stdin().read_line(&mut line).unwrap();
        let mut iter = line.split_whitespace();
        (
            iter.next().unwrap().parse().unwrap(),
            iter.next().unwrap().parse().unwrap(),
        )
    }
}

fn main() {
    let n: usize = util::get();
    let (c, v): (usize, usize) = util::get2();

    // dp[i] = i文字のときのコスト
    let mut dp = vec![None; n + 1];

    dp[1] = Some(0);
    let mut updated = true;
    while updated {
        updated = false;
        for k in 1..n + 1 {
            if let Some(current_cost) = dp[k] {
                // copy here
                let mut m = k;
                let mut cost = current_cost + c;

                // paste
                while m < n {
                    m = min(m + k, n);
                    cost += v;
                    if dp[m].map(|cm| cm > cost).unwrap_or(true) {
                        dp[m] = Some(cost);
                        updated = true;
                    }
                }
            }
        }
    }

    println!("{}", dp[n].unwrap());
}