fn main() {
    let mut nmp = String::new();
    std::io::stdin().read_line(&mut nmp).ok();
    let nmp: Vec<usize> = nmp.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
    let n = nmp[0];
    let m = nmp[1];
    let p = nmp[2];
    let mut a = String::new();
    std::io::stdin().read_line(&mut a).ok();
    let a: Vec<usize> = a.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();

    let maxval = *a.iter().max().unwrap();
    let mut cnt2val = vec![0usize; 31];
    for &v in a.iter() {
        let mut cnt = 1usize;
        let mut target = v;
        while target % p == 0 {
            target /= p;
            cnt += 1;
        }
        cnt2val[cnt] = cnt2val[cnt].max(target);
    }
    let mut dp = vec![vec![0usize; 1000]; 32];
    dp[0][1] = maxval;
    for i in 1..=31 {
        for j in 0..1000 {
            dp[i][j] = dp[i][j].max(dp[i-1][j]).min(m+1);
            for acnt in 0..=30 {
                if cnt2val[acnt] <= 1 { continue; }
                if j >= acnt {
                    dp[i][j] = dp[i][j].max(dp[i][j-acnt] * cnt2val[acnt]).min(m+1);
                }
            }
        }
    }
    if let Some(idx) = (0..1000).filter(|&i| dp[31][i] > m).nth(0) {
        println!("{}", idx);
    } else {
        println!("-1");
    }
}