Problem:
Score : 500 points

Problem Statement

Takahashi is at an all-you-can-eat restaurant.

The restaurant offers N kinds of dishes. It takes A_i minutes to eat the i-th dish, whose deliciousness is B_i.

The restaurant has the following rules:

You can only order one dish at a time. The dish ordered will be immediately served and ready to eat.

You cannot order the same kind of dish more than once.

Until you finish eating the dish already served, you cannot order a new dish.

After T-0.5 minutes from the first order, you can no longer place a new order, but you can continue eating the dish already served.

Let Takahashi's happiness be the sum of the deliciousness of the dishes he eats in this restaurant.

What is the maximum possible happiness achieved by making optimal choices?

Constraints

2 \leq N \leq 3000

1 \leq T \leq 3000

1 \leq A_i \leq 3000

1 \leq B_i \leq 3000

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N T
A_1 B_1
:
A_N B_N

Output

Print the maximum possible happiness Takahashi can achieve.

Sample Input 1

2 60
10 10
100 100

Sample Output 1

110

By ordering the first and second dishes in this order, Takahashi's happiness will be 110.

Note that, if we manage to order a dish in time, we can spend any amount of time to eat it.

Sample Input 2

3 60
10 10
10 20
10 30

Sample Output 2

60

Takahashi can eat all the dishes within 60 minutes.

Sample Input 3

3 60
30 10
30 20
30 30

Sample Output 3

50

By ordering the second and third dishes in this order, Takahashi's happiness will be 50.

We cannot order three dishes, in whatever order we place them.

Sample Input 4

10 100
15 23
20 18
13 17
24 12
18 29
19 27
23 21
18 20
27 15
22 25

Sample Output 4

145

Solution in Rust (1.15.1) (judge verdict: Accepted)

// SNIPPET bitset
const BITSET_TRUE: &'static bool = &true;
const BITSET_FALSE: &'static bool = &false;
#[derive(Clone, Debug)]
pub struct BitSet {
    buf: Vec<u64>,
    size: usize,
}
impl BitSet {
    pub fn new(size: usize) -> BitSet {
        BitSet {
            buf: vec![0; (size + 63) / 64],
            size: size,
        }
    }
    pub fn get(&mut self, i: usize) -> Option<bool> {
        if i <= self.size {
            Some(self.buf[i >> 6] & 1 << (i & 63) != 0)
        } else {
            None
        }
    }
    pub fn get_mut(&mut self, i: usize) -> Option<BitSetRef> {
        self.get(i).map(move |b| BitSetRef {
            bitset: self,
            value: b,
            index: i
        })
    }
    pub fn at(&mut self, i: usize) -> BitSetRef {
        self.get_mut(i).unwrap()
    }
    pub fn count_ones(&self) -> u32 {
        self.buf.iter().map(|x| x.count_ones()).sum()
    }
    fn chomp(&mut self) {
        let r = self.size & 63;
        if r != 0 {
            if let Some(x) = self.buf.last_mut() {
                let d = 64 - r;
                *x = (*x << d) >> d;
            }
        }
    }
}
impl std::ops::Index<usize> for BitSet {
    type Output = bool;
    fn index(&self, index: usize) -> &bool {
        [BITSET_FALSE, BITSET_TRUE][(self.buf[index >> 6] >> (index & 63)) as usize & 1]
    }
}
pub struct BitSetRef<'a> {
    bitset: &'a mut BitSet,
    value: bool,
    index: usize
}
impl<'a> std::ops::Deref for BitSetRef<'a> {
    type Target = bool;
    fn deref(&self) -> &bool {
        &self.value
    }
}
impl<'a> std::ops::DerefMut for BitSetRef<'a> {
    fn deref_mut(&mut self) -> &mut bool {
        &mut self.value
    }
}
impl<'a> Drop for BitSetRef<'a> {
    fn drop(&mut self) {
        if self.value {
            self.bitset.buf[self.index >> 6] |= 1 << (self.index & 63);
        } else {
            self.bitset.buf[self.index >> 6] &= !(1 << (self.index & 63));
        }
    }
}
impl std::ops::ShlAssign<usize> for BitSet {
    fn shl_assign(&mut self, x: usize) {
        let q = x >> 6;
        let r = x & 63;
        if q >= self.buf.len() {
            for x in &mut self.buf {
                *x = 0;
            }
            return;
        }
        if r == 0 {
            for i in (q..self.buf.len()).rev() {
                self.buf[i] = self.buf[i - q];
            }
        } else {
            for i in (q + 1..self.buf.len()).rev() {
                self.buf[i] = (self.buf[i - q] << r) | (self.buf[i - q - 1] >> (64 - r));
            }
            self.buf[q] = self.buf[0] << r;
        }
        for x in &mut self.buf[..q] {
            *x = 0;
        }
        self.chomp();
    }
}
impl std::ops::Shl<usize> for BitSet {
    type Output = Self;
    fn shl(mut self, x: usize) -> Self {
        self <<= x;
        self
    }
}
impl std::ops::ShrAssign<usize> for BitSet {
    fn shr_assign(&mut self, x: usize) {
        let q = x >> 6;
        let r = x & 63;
        if q >= self.buf.len() {
            for x in &mut self.buf {
                *x = 0;
            }
            return;
        }
        if r == 0 {
            for i in 0..self.buf.len() - q {
                self.buf[i] = self.buf[i + q];
            }
        } else {
            for i in 0..self.buf.len() - q - 1 {
                self.buf[i] = (self.buf[i + q] >> r) | (self.buf[i + q + 1] << (64 - r));
            }
            let len = self.buf.len();
            self.buf[len - q - 1] = self.buf[len - 1] >> r;
        }
        let len = self.buf.len();
        for x in &mut self.buf[len - q..] {
            *x = 0;
        }
    }
}
impl std::ops::Shr<usize> for BitSet {
    type Output = Self;
    fn shr(mut self, x: usize) -> Self {
        self >>= x;
        self
    }
}
impl<'a> std::ops::BitAndAssign<&'a BitSet> for BitSet {
    fn bitand_assign(&mut self, rhs: &'a Self) {
        for (a, b) in self.buf.iter_mut().zip(rhs.buf.iter()) {
            *a &= *b;
        }
    }
}
impl<'a> std::ops::BitAnd<&'a BitSet> for BitSet {
    type Output = Self;
    fn bitand(mut self, rhs: &'a Self) -> Self {
        self &= rhs;
        self
    }
}
impl<'a> std::ops::BitOrAssign<&'a BitSet> for BitSet {
    fn bitor_assign(&mut self, rhs: &'a Self) {
        for (a, b) in self.buf.iter_mut().zip(rhs.buf.iter()) {
            *a |= *b;
        }
        self.chomp();
    }
}
impl<'a> std::ops::BitOr<&'a BitSet> for BitSet {
    type Output = Self;
    fn bitor(mut self, rhs: &'a Self) -> Self {
        self |= rhs;
        self
    }
}
impl<'a> std::ops::BitXorAssign<&'a BitSet> for BitSet {
    fn bitxor_assign(&mut self, rhs: &'a Self) {
        for (a, b) in self.buf.iter_mut().zip(rhs.buf.iter()) {
            *a ^= *b;
        }
        self.chomp();
    }
}
impl<'a> std::ops::BitXor<&'a BitSet> for BitSet {
    type Output = Self;
    fn bitxor(mut self, rhs: &'a Self) -> Self {
        self ^= rhs;
        self
    }
}
// SNIPPET read
pub trait Readable {
    type Output;
    fn words_count() -> usize;
    fn read_words(words: &[&str]) -> Result<Self::Output, String>;
}
#[macro_export]
macro_rules! readable {
    ( $t:ty, $words_count:expr, |$words:ident| $read_words:expr ) => {
        impl Readable for $t {
            type Output = $t;
            fn words_count() -> usize { $words_count }
            fn read_words($words: &[&str]) -> Result<$t, String> {
                Ok($read_words)
            }
        }
    };
}
readable!((), 1, |_ss| ());
readable!(String, 1, |ss| ss[0].to_string());
impl Readable for char {
    type Output = char;
    fn words_count() -> usize { 1 }
    fn read_words(words: &[&str]) -> Result<char, String> {
        let chars: Vec<char> = words[0].chars().collect();
        if chars.len() == 1 {
            Ok(chars[0])
        } else {
            Err(format!("cannot parse `{}` as a char", words[0]))
        }
    }
}
pub struct Chars();
impl Readable for Chars {
    type Output = Vec<char>;
    fn words_count() -> usize { 1 }
    fn read_words(words: &[&str]) -> Result<Vec<char>, String> {
        Ok(words[0].chars().collect())
    }
}
macro_rules! impl_readable_for_ints {
    ( $( $t:ty )* ) => { $(
        impl Readable for $t {
            type Output = Self;
            fn words_count() -> usize { 1 }
            fn read_words(words: &[&str]) -> Result<$t, String> {
                use std::str::FromStr;
                <$t>::from_str(words[0]).map_err(|_| {
                    format!("cannot parse `{}` as {}", words[0], stringify!($t))
                })
            }
        }
    )* };
}
impl_readable_for_ints!(i8 u8 i16 u16 i32 u32 i64 u64 isize usize f32 f64);
macro_rules! define_one_origin_int_types {
    ( $new_t:ident $int_t:ty ) => {
        #[allow(non_camel_case_types)]
        pub struct $new_t;
        impl Readable for $new_t {
            type Output = $int_t;
            fn words_count() -> usize { 1 }
            fn read_words(words: &[&str]) -> Result<Self::Output, String> {
                <$int_t>::read_words(words).map(|n| n-1)
            }
        }
    };
    ( $new_t:ident $int_t:ty; $( $inner_new_t:ident $inner_int_t:ty );* ) => {
        define_one_origin_int_types!($new_t $int_t);
        define_one_origin_int_types!($($inner_new_t $inner_int_t);*);
    };
}
define_one_origin_int_types!(u8_ u8; u16_ u16; u32_ u32; u64_ u64; usize_ usize);
macro_rules! impl_readable_for_tuples {
    ( $t:ident $var:ident ) => ();
    ( $t:ident $var:ident; $( $inner_t:ident $inner_var:ident );* ) => {
        impl_readable_for_tuples!($($inner_t $inner_var);*);
        impl<$t: Readable, $($inner_t: Readable),*> Readable
            for ($t, $($inner_t),*)
        {
            type Output = ( <$t>::Output, $(<$inner_t>::Output),* );
            fn words_count() -> usize {
                let mut n = <$t>::words_count();
                $(
                    n += <$inner_t>::words_count();
                )*
                n
            }
            #[allow(unused_assignments)]
            fn read_words(words: &[&str]) ->
                Result<Self::Output, String>
            {
                let mut start = 0;
                let $var = <$t>::read_words(
                    &words[start .. start+<$t>::words_count()]
                )?;
                start += <$t>::words_count();
                $(
                    let $inner_var =
                        <$inner_t>::read_words(
                            &words[start .. start+<$inner_t>::words_count()]
                        )?;
                    start += <$inner_t>::words_count();
                )*
                Ok(( $var, $($inner_var),* ))
            }
        }
    };
}
impl_readable_for_tuples!(T8 x8; T7 x7; T6 x6; T5 x5; T4 x4; T3 x3; T2 x2; T1 x1);
pub trait ReadableFromLine {
    type Output;
    fn read_line(line: &str) -> Result<Self::Output, String>;
}
fn split_into_words(line: &str) -> Vec<&str> {
    #[allow(deprecated)]
    line.trim_right_matches('\n').split_whitespace().collect()
}
impl<T: Readable> ReadableFromLine for T {
    type Output = T::Output;
    fn read_line(line: &str) -> Result<T::Output, String> {
        let words = split_into_words(line);
        if words.len() != T::words_count() {
            return Err(format!("line `{}` has {} words, expected {}",
                               line, words.len(), T::words_count()));
        }
        T::read_words(&words)
    }
}
macro_rules! impl_readable_from_line_for_tuples_with_from_iterator {
    ( $u:ident : $( + $bound:path )* => $seq_in:ty, $seq_out:ty; $t:ident $var:ident ) => {
        impl<$u: Readable> ReadableFromLine for $seq_in
        where
            <$u as Readable>::Output: Sized $(+ $bound)*
        {
            type Output = $seq_out;
            fn read_line(line: &str) -> Result<$seq_out, String> {
                let n = $u::words_count();
                let words = split_into_words(line);
                if words.len() % n != 0 {
                    return Err(format!("line `{}` has {} words, expected multiple of {}",
                                       line, words.len(), n));
                }
                let mut result = Vec::new();
                for chunk in words.chunks(n) {
                    match $u::read_words(chunk) {
                        Ok(v) => result.push(v),
                        Err(msg) => {
                            let flagment_msg = if n == 1 {
                                format!("word {}", result.len())
                            } else {
                                let l = result.len();
                                format!("words {}-{}", n*l + 1, (n+1) * l)
                            };
                            return Err(format!(
                                "{} of line `{}`: {}", flagment_msg, line, msg
                            ));
                        }
                    }
                }
                Ok(result.into_iter().collect())
            }
        }
        impl<T: Readable, $u: Readable> ReadableFromLine for (T, $seq_in)
        where
            <$u as Readable>::Output: Sized $(+ $bound)*
        {
            type Output = (T::Output, $seq_out);
            fn read_line(line: &str) -> Result<Self::Output, String> {
                let n = T::words_count();
                #[allow(deprecated)]
                let trimmed = line.trim_right_matches('\n');
                let words_and_rest: Vec<&str> = trimmed.splitn(n + 1, ' ').collect();
                if words_and_rest.len() < n {
                    return Err(format!("line `{}` has {} words, expected at least {}",
                                       line, words_and_rest.len(), n));
                }
                let words = &words_and_rest[..n];
                let empty_str = "";
                let rest = words_and_rest.get(n).unwrap_or(&empty_str);
                Ok((T::read_words(words)?, <$seq_in>::read_line(rest)?))
            }
        }
    };
    ( $u:ident : $( + $bound:path )* => $seq_in:ty, $seq_out:ty;
      $t:ident $var:ident, $( $inner_t:ident $inner_var:ident ),+ ) => {
        impl_readable_from_line_for_tuples_with_from_iterator!(
            $u: $(+ $bound)* => $seq_in, $seq_out; $($inner_t $inner_var),+
        );
        impl<$t: Readable, $($inner_t: Readable),+ , $u: Readable> ReadableFromLine
            for ($t, $($inner_t),+ , $seq_in)
        where
            <$u as Readable>::Output: Sized $(+ $bound)*
        {
            type Output = ($t::Output, $($inner_t::Output),+ , $seq_out);
            fn read_line(line: &str) -> Result<Self::Output, String> {
                let mut n = $t::words_count();
                $(
                    n += $inner_t::words_count();
                )+
                #[allow(deprecated)]
                let trimmed = line.trim_right_matches('\n');
                let words_and_rest: Vec<&str> = trimmed.splitn(n + 1, ' ')
                    .collect();
                if words_and_rest.len() < n {
                    return Err(
                        format!("line `{}` has {} words, expected at least {}",
                                line, words_and_rest.len(), n)
                    );
                }
                let words = &words_and_rest[..n];
                let empty_str = "";
                let rest = words_and_rest.get(n).unwrap_or(&empty_str);
                let ($var, $($inner_var),*) =
                    <($t, $($inner_t),+)>::read_words(words)?;
                Ok(($var, $($inner_var),* , <$seq_in>::read_line(rest)?))
            }
        }
    };
}
#[macro_export]
macro_rules! readable_collection {
    ($u:ident => $collection_in:ty, $collection_out:ty) => {
        impl_readable_from_line_for_tuples_with_from_iterator!(
            $u: => $collection_in, $collection_out;
            T8 x8, T7 x7, T6 x6, T5 x5, T4 x4, T3 x3, T2 x2, T1 x1
        );
    };
    ($u:ident : $( $bound:path ),* => $collection_in:ty, $collection_out:ty) => {
        impl_readable_from_line_for_tuples_with_from_iterator!(
            $u: $(+ $bound)* => $collection_in, $collection_out;
            T8 x8, T7 x7, T6 x6, T5 x5, T4 x4, T3 x3, T2 x2, T1 x1
        );
    }
}
readable_collection!(U => Vec<U>, Vec<U::Output>);
readable_collection!(
    U => std::collections::VecDeque<U>, std::collections::VecDeque<U::Output>
);
readable_collection!(
    U: Eq, std::hash::Hash => std::collections::HashSet<U>, std::collections::HashSet<U::Output>
);
readable_collection!(
    U: Ord => std::collections::BTreeSet<U>, std::collections::BTreeSet<U::Output>
);
readable_collection!(
    U: Ord => std::collections::BinaryHeap<U>, std::collections::BinaryHeap<U::Output>
);
pub fn read<T: ReadableFromLine>() -> T::Output {
    let mut line = String::new();
    std::io::stdin().read_line(&mut line).unwrap();
    T::read_line(&line).unwrap()
}
#[macro_export]
macro_rules! read {
    () => {
        let mut line = String::new();
        std::io::stdin().read_line(&mut line).unwrap();
    };
    ( $pat:pat = $t:ty ) => {
        let $pat = read::<$t>();
    };
    ( $( $pat:pat = $t:ty ),+ ) => {
        read!(($($pat),*) = ($($t),*));
    };
}
#[macro_export]
macro_rules! readls {
    ( $( $pat:pat = $t:ty ),+ ) => {
        $(
            read!($pat = $t);
        )*
    };
}
pub fn readx<T: ReadableFromLine>() -> Vec<T::Output> {
    use std::io::{self, BufRead};
    let stdin = io::stdin();
    let result = stdin.lock().lines().map(|line_result| {
        let line = line_result.expect("read from stdin failed");
        T::read_line(&line).unwrap()
    }).collect();
    result
}
#[macro_export]
macro_rules! readx_loop {
    ( |$pat:pat = $t:ty| $body:expr ) => {
        {
            use std::io::BufRead;
            let stdin = std::io::stdin();
            for line in stdin.lock().lines() {
                let line = line.expect("read from stdin failed");
                let $pat = <$t>::read_line(&line).unwrap();
                $body
            }
        }
    };
    ( |$($pat:pat = $t:ty),*| $body:expr ) => {
        readx_loop!(|($($pat),*) = ($($t),*)| $body);
    };
}
pub fn readn<T: ReadableFromLine>(n: usize) -> Vec<T::Output> {
    use std::io::{self, BufRead};
    let stdin = io::stdin();
    let result: Vec<T::Output> = stdin.lock().lines().take(n).map(|line_result| {
        let line = line_result.expect("read from stdin failed");
        T::read_line(&line).unwrap()
    }).collect();
    if result.len() < n {
        panic!("expected reading {} lines, but only {} lines are read",
               n, result.len());
    }
    result
}
#[macro_export]
macro_rules! readn_loop {
    ( $n:expr, |$pat:pat = $t:ty| $body:expr ) => {
        {
            use std::io::BufRead;
            let stdin = std::io::stdin();
            let mut lock = stdin.lock();
            for _ in 0..$n {
                let mut line = String::new();
                lock.read_line(&mut line).expect("read from stdin failed");
                let $pat = <$t>::read_line(&line).unwrap();
                $body
            }
        }
    };
    ( $n:expr, |$($pat:pat = $t:ty),*| $body:expr ) => {
        readn_loop!($n, |($($pat),*) = ($($t),*)| $body);
    };
}
pub trait Words {
    fn read<T: Readable>(&self) -> T::Output;
}
impl<'a> Words for [&'a str] {
    fn read<T: Readable>(&self) -> T::Output {
        T::read_words(self).unwrap()
    }
}
impl<'a> Words for &'a str {
    fn read<T: Readable>(&self) -> T::Output {
        T::read_words(&[self]).unwrap()
    }
}

/*
fn knapsack(len: usize, t: u16, foods: &[(u16, u32)], memo: mut Vec<Vec<Option<(BitSet, u32)>>>) -> (BitSet, u32) {
    memo[len][t as usize].clone().unwrap_or_else(|| {
        let ans = if len == 0 {
            (BitSet::new(foods.len()), 0)
        } else {
            let (t_i, v_i) = foods[len-1];
            if t_i > t {
                knapsack(len-1, t, foods, memo)
            } else {
                let (s1, v1) = knapsack(len-1, t, foods, memo);
                let (mut s2, v2) = knapsack(len-1, t-t_i, foods, memo);
                if v1 >= v2+v_i {
                    (s1, v1)
                } else {
                    *s2.at(len-1) = true;
                    (s2, v2 + v_i)
                }
            }
        };
        memo[len][t as usize] = Some(ans.clone());
        ans
    })
}
 */

use std::cmp;

fn main() {
    read!(n = usize, t_max = usize);
    let foods = readx::<(usize, usize)>();
    let mut dp = vec![vec![(false, 0); t_max]; n+1];
    for i in 0..n {
        let (t_i, v_i) = foods[i];
        for t in 0..cmp::min(t_i, t_max) {
            dp[i+1][t] = (false, dp[i][t].1);
        }
        for t in cmp::min(t_i, t_max)..t_max {
            let v1 = dp[i][t].1;
            let v2 = dp[i][t-t_i].1;
            if v1 >= v2+v_i {
                dp[i+1][t] = (false, v1)
            } else {
                dp[i+1][t] = (true, v2+v_i);
            }
        }
    }
    let mut set = vec![false; n];
    let mut t = t_max-1;
    for i in (1..n+1).rev() {
        if dp[i][t].0 {
            set[i-1] = true;
            t -= foods[i-1].0;
        }
    }
    let val = dp[n][t_max-1].1;
    let ans = val + (0..n).filter(|&i| !set[i]).map(|i| foods[i].1).max().unwrap_or(0);
    println!("{}", ans);
}