const INF: usize = 1usize << 60;

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

    let mut costs = vec![INF; n+1];
    costs[1] = 0;
    for i in 1..n {
        for j in 1.. {
            let idx = (i + i * j).min(n);
            costs[idx] = costs[idx].min(costs[i] + c + j * v);
            if idx == n { break; }
        }
    }
    println!("{}", costs[n]);
}