macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
    ($($r:tt)*) => {
        #[warn(unused_mut)]
        let mut s = {
            use std::io::Read;
            let mut s = String::new();
            std::io::stdin().read_to_string(&mut s).unwrap();
            s
        };
        let mut iter = s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
}

macro_rules! input_inner {
    ($iter:expr) => {};
    ($iter:expr, ) => {};

    ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
}

macro_rules! read_value {
    ($iter:expr, ( $($t:tt),* )) => {
        ( $(read_value!($iter, $t)),* )
    };

    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };

    ($iter:expr, chars) => {
        read_value!($iter, String).chars().collect::<Vec<char>>()
    };

    ($iter:expr, usize1) => {
        read_value!($iter, usize) - 1
    };

    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}

fn main() {
    input!{
        n:usize, k:i64, q:usize,
        a:[i64; n]
    };
    let ia = a.iter().enumerate().collect::<Vec<(usize, &i64)>>();
    let mut ord = ia.clone();
    ord.sort_by_key(|&(_, ai)| ai);
    let mut res = 100_000_000_000_000_000;
    for i in 0..n + 1 {
        let mut r = ord[0..i].iter().map(|&(i, _)| i).collect::<Vec<usize>>();
        r.sort();
        let sp = ia.split(|&(i, _)| r.binary_search(&i).is_ok());
        let sp = sp.map(|x| x.iter().map(|&(_, &ai)| ai));
        let aq = sp
            .flat_map(|x| {
                let mut s: Vec<i64> = x.collect();
                s.sort();
                let m = s.len() as i64 + 1 - k;
                let m = if m < 0 { 0 } else { m as usize };
                s[0..m].to_vec()
            }).collect::<Vec<i64>>();
        if aq.len() < q {
            break;
        }
        aq.sort()
        let r = aq[q - 1] - aq[0];
        if r < res {
            res = r
        };
    }
    println!("{}", res);
}
