#![allow(unused_imports)]
use std::cmp::*;
use std::collections::*;
use std::io::Write;
use std::ops::Bound::*;

#[allow(unused_macros)]
macro_rules! debug {
    ($($e:expr),*) => {
        #[cfg(debug_assertions)]
        $({
            let (e, mut err) = (stringify!($e), std::io::stderr());
            writeln!(err, "{} = {:?}", e, $e).unwrap()
        })*
    };
}

fn main() {
    let v = read_vec::<i64>();
    let (n, m, p) = (v[0] as usize, v[1], v[2]);
    let a = read_vec::<i64>();
    let amax = *a.iter().max().unwrap();
    let mut aa = vec![];
    let mut counts = vec![];
    for mut num in a {
        let mut count = 1usize;
        while num % p == 0 {
            num /= p;
            count += 1usize;
        }
        aa.push(num);
        counts.push(count);
    }
    // debug!(aa);
    let aa_max = *aa.iter().max().unwrap();
    if aa_max == 1 && amax <= m {
        println!("-1");
        return;
    }
    if m == 1 {
        println!("0");
        return;
    }

    let mut dp = vec![0i64; 1000];
    dp[0] = 1;
    for i in 0..dp.len() - 1 {
        if dp[i] > m {
            break;
        }
        for j in 0..n {
            if i + counts[j] >= dp.len() {
                continue;
            }
            dp[i + counts[j]] = max(dp[i + counts[j]], dp[i] * aa[j]);
        }
    }
    for i in 0..dp.len() {
        if dp[i] * amax > m {
            println!("{}", i + 1);
            return;
        }
    }
}

fn read<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}

fn read_vec<T: std::str::FromStr>() -> Vec<T> {
    read::<String>()
        .split_whitespace()
        .map(|e| e.parse().ok().unwrap())
        .collect()
}