use std::{cmp::Reverse, collections::BinaryHeap};

use proconio::input;

fn solve() -> i64 {
  input! {
    n: usize,
    k: usize,
    x: i64,
    a: [i64; n],
  }
  let mut q = BinaryHeap::new();
  let mut s = 0;
  let mut ans = i64::MIN;
  for (i, &ai) in a.iter().enumerate() {
    q.push(Reverse(ai));
    s += ai;
    if q.len() > k {
      s -= q.pop().unwrap().0;
    }
    ans = ans.max(s - (i as i64 + 1) * x);
  }
  ans
}

fn main() {
  let ans = solve();
  println!("{}", ans);
}