use proconio::input;

fn main () {
    input! {
        n: usize,
        k: usize,
        a: [i128; n],
        b: [i128; n],
        c: [i128; n],
    }
    let mut dif = b.iter()
        .zip(c.iter())
        .enumerate()
        .map(|(i, (b, c))| {
            (b-c, i)
        })
        .collect::<Vec<_>>();
    dif.sort_by(|a, b| b.cmp(a));
    let mut ac = a.iter()
        .zip(c.iter())
        .map(|(a, c)| a+c )
        .collect::<Vec<_>>();
    for (i, v) in dif.iter().enumerate() {
        if i >= k {break;}
        ac[v.1] += v.0;
    }
    println!("{}", ac.iter().sum::<i128>());
    
}