use proconio::*;

fn main() {
    input! {
        n: usize,
        a: f64,
        b: f64,
        k: [f64; n+1],
    }
    let mut ans: (f64, f64) = (0., 0.);
    for (xa, xb) in (1..=n+1).zip(k.into_iter()) {
        let xa = xa as f64;
        ans.0 += (xb/xa)*a.powf(xa);
        ans.1 += (xb/xa)*b.powf(xa);
    }
    let ans = (ans.1 - ans.0).floor() as isize;
    println!("{ans}");
}