use std::io::Read;

fn run() {
    let mut s = String::new();
    std::io::stdin().read_to_string(&mut s).unwrap();
    let mut it = s.trim().split_whitespace();
    let n: usize = it.next().unwrap().parse().unwrap();
    let w: usize = it.next().unwrap().parse().unwrap();
    let mut p: Vec<(usize, i32)> = (0..n).map(|_| {
        let p: usize = it.next().unwrap().parse().unwrap();
        let d: i32 = it.next().unwrap().parse().unwrap();
        (p, d)
    }).collect();
    p.sort();
    let mut now = vec![vec![std::i32::MIN; w + 1]; 2];
    now[0] = vec![0; w + 1];
    let mut next = now.clone();
    for (p, d) in p.into_iter().rev() {
        next.clone_from(&now);
        for (next, now) in next[1][p..].iter_mut().zip(now[0].iter()) {
            *next = std::cmp::max(*next, *now + d);
        }
        for (next, now) in next[0].iter_mut().zip(now[1].iter()) {
            *next = std::cmp::max(*next, *now + d);
        }
        std::mem::swap(&mut now, &mut next);
    }
    let ans = std::cmp::max(now[0][w], now[1][w]);
    println!("{}", ans);
}

fn main() {
    run();
}