#[allow(unused_imports)]
use std::cmp::*;
#[allow(unused_imports)]
use std::collections::*;

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()
}

fn argsort<T: std::cmp::Ord + std::marker::Copy>(v: &Vec<T>) -> Vec<usize> {
    let mut sort_v = Vec::new();
    for i in 0..v.len() {
        sort_v.push((v[i], i));
    }
    sort_v.sort();
    sort_v.iter().map(|x| x.1).collect::<Vec<usize>>()
}

fn construct_usables(k: usize, min_candidate_a: u64, a: &Vec<u64>) -> Vec<u64> {
    let mut usables = Vec::new();

    let mut is_seeking = false;
    let mut start_seeking_index = 0usize;

    for j in 0..a.len() {
        if a[j] >= min_candidate_a {
            if !is_seeking {
                is_seeking = true;
                start_seeking_index = j;
            }
        }
        if is_seeking && (a[j] < min_candidate_a || j == a.len() - 1) {
            let mut end_idx = j;
            if j == a.len() - 1 {
                end_idx += 1;
            }
            is_seeking = false;
            if end_idx - start_seeking_index < k {
                continue;
            }

            let mut pocket_values = Vec::new();
            for ii in start_seeking_index..end_idx {
                pocket_values.push(a[ii]);
            }
            pocket_values.sort();

            let width = end_idx - start_seeking_index;
            if width + 1 >= k {
                for ii in 0..width + 1 - k {
                    usables.push(pocket_values[ii]);
                }
            }
        }
    }
    usables.sort();
    usables
}

fn main() {
    let v = read_vec::<usize>();
    let (n, k, q) = (v[0], v[1], v[2]);
    let a = read_vec::<u64>();

    let mut ans = std::u64::MAX;
    for i in 0..n {
        let min_candidate_a = a[i];
        let usables = construct_usables(k, min_candidate_a, &a);
        if usables.len() >= q {
            // assert_eq!(usables[0], min_candidate_a);
            ans = min(ans, usables[q - 1] - min_candidate_a);
        }
    }
    println!("{}", ans);
}
