use std::cmp::Reverse;


fn main() {
    let mut nmx = String::new();
    std::io::stdin().read_line(&mut nmx).ok();
    let nmx: Vec<usize> = nmx.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
    let n = nmx[0];
    let m = nmx[1];
    let x = nmx[2];
    let mut problems = (0..n).map(|_| {
            let mut temp = String::new();
            std::io::stdin().read_line(&mut temp).ok();
            let temp: Vec<usize> = temp.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
            (temp[0], temp[1]-1)
        })
        .collect::<Vec<_>>();
    let mut k = String::new();
    std::io::stdin().read_line(&mut k).ok();
    let k: usize = k.trim().parse().unwrap();
    let mut c = String::new();
    std::io::stdin().read_line(&mut c).ok();
    let c: Vec<usize> = c.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();

    let mut ccnt = vec![0usize; n+1];
    for &v in c.iter() { ccnt[v] += 1; }
    problems.sort_by_key(|&(s, _)| Reverse(s));
    let mut scores = Vec::with_capacity(n);
    let mut used = vec![false; m];
    for &(score, pat) in problems.iter() {
        scores.push(score + if !used[pat] { x } else { 0 });
        used[pat] = true;
    }
    scores.sort_by_key(|&v| Reverse(v));
    let mut summary = 0usize;
    let mut result = 0usize;
    for i in 0..n {
        summary += scores[i];
        result += ccnt[i+1] * summary;
    }
    println!("{}", result);
}