#![allow(unused_imports, unused_macros, dead_code)]
use std::cmp::*;
use std::collections::*;

macro_rules! min {
    (.. $x:expr) => {{
        let mut it = $x.iter();
        it.next().map(|z| it.fold(z, |x, y| min!(x, y)))
    }};
    ($x:expr) => ($x);
    ($x:expr, $($ys:expr),*) => {{
        let t = min!($($ys),*);
        if $x < t { $x } else { t }
    }}
}
macro_rules! max {
    (.. $x:expr) => {{
        let mut it = $x.iter();
        it.next().map(|z| it.fold(z, |x, y| max!(x, y)))
    }};
    ($x:expr) => ($x);
    ($x:expr, $($ys:expr),*) => {{
        let t = max!($($ys),*);
        if $x > t { $x } else { t }
    }}
}
macro_rules! trace {
    ($x:expr) => {
        #[cfg(debug_assertions)]
        eprintln!(">>> {} = {:?}", stringify!($x), $x)
    };
    ($($xs:expr),*) => { trace!(($($xs),*)) }
}
macro_rules! put {
    (.. $x:expr) => {{
        let mut it = $x.iter();
        if let Some(x) = it.next() { print!("{}", x); }
        for x in it { print!(" {}", x); }
        println!("");
    }};
    ($x:expr) => { println!("{}", $x) };
    ($x:expr, $($xs:expr),*) => { print!("{} ", $x); put!($($xs),*) }
}

fn main() {
    let mut sc = Scanner::new();
    let n: usize = sc.cin();
    let m: u64 = sc.cin();
    let p: u64 = sc.cin();

    let mut xs = vec![];

    const M: usize = 10_000;
    let mut memo = vec![1; M];

    for _ in 0..n {
        let mut x: u64 = sc.cin();
        let mut a = 0;
        while x % p == 0 {
            a += 1;
            x /= p;
        }
        xs.push((x, a));
    }

    let mut ans = 100_000;

    for k in 0..200 {
        for &(x, a) in xs.iter() {
            if k + 1 + a < M {
                if memo[k + 1 + a] > m {
                    continue;
                }
                // trace!(memo[k], x);
                memo[k + 1 + a] = max!(memo[k + 1 + a], memo[k] * x);
                if memo[k + 1 + a] > m {
                    ans = min!(ans, k + 1 + a);
                }
            }
        }
    }

    if ans == 100_000 {
        put!(-1);
    } else {
        put!(ans);
    }
}

use std::collections::VecDeque;
use std::io::{self, Write};
use std::str::FromStr;

struct Scanner {
    stdin: io::Stdin,
    buffer: VecDeque<String>,
}
impl Scanner {
    fn new() -> Self {
        Scanner {
            stdin: io::stdin(),
            buffer: VecDeque::new(),
        }
    }
    fn cin<T: FromStr>(&mut self) -> T {
        while self.buffer.is_empty() {
            let mut line = String::new();
            let _ = self.stdin.read_line(&mut line);
            for w in line.split_whitespace() {
                self.buffer.push_back(String::from(w));
            }
        }
        self.buffer.pop_front().unwrap().parse::<T>().ok().unwrap()
    }
    fn chars(&mut self) -> Vec<char> {
        self.cin::<String>().chars().collect()
    }
    fn vec<T: FromStr>(&mut self, n: usize) -> Vec<T> {
        (0..n).map(|_| self.cin()).collect()
    }
}
fn flush() {
    std::io::stdout().flush().unwrap();
}