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 C (Clang 3.8.0) (judge verdict: Accepted)

#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <inttypes.h>
#include <limits.h>
#include <ctype.h>
#include <stdint.h>
#include <string.h>
#include <wchar.h>
#include <math.h>

#define N_MAX (100)
#define P_MAX (100)
#define DP_ARRAY_SIZE (N_MAX * P_MAX / 32 + 1)

#define MIN(a, b) ((a) < (b) ? (a) : (b))
#define MAX(a, b) ((a) > (b) ? (a) : (b))
#define ABS(a) ((a) < 0 ? -(a) : (a))
#define ABSS(a, b) ((a) > (b) ? (a) - (b) : (b) - (a))
#define SWAP(type, a, b) { const type tmp = a; a = b; b = tmp; }

int compare_sz_asc(const void* a, const void* b) {
    return *((size_t*)a) < *((size_t*)b) ? -1 : 1;
}

int compare_sz_desc(const void* a, const void* b) {
    return *((size_t*)a) > * ((size_t*)b) ? -1 : 1;
}

int compare_i64_asc(const void* a, const void* b) {
    return *((int64_t*)a) < *((int64_t*)b) ? -1 : 1;
}

int compare_i64_desc(const void* a, const void* b) {
    return *((int64_t*)a) > * ((int64_t*)b) ? -1 : 1;
}

int compare_u64_asc(const void* a, const void* b) {
    return *((uint64_t*)a) < *((uint64_t*)b) ? -1 : 1;
}

int compare_u64_desc(const void* a, const void* b) {
    return *((uint64_t*)a) > * ((uint64_t*)b) ? -1 : 1;
}

int compare_c_asc(const void* a, const void* b) {
    return *((char*)a) < *((char*)b) ? -1 : 1;
}

int compare_c_desc(const void* a, const void* b) {
    return *((char*)a) > * ((char*)b) ? -1 : 1;
}

int compare_dp_asc(const void* a, const void* b) {
    return *((double*)a) < *((double*)b) ? -1 : 1;
}

static uint64_t modinvU64(const uint64_t a, const uint64_t m) {
    int64_t aa = (int64_t)a;
    const int64_t mm = (int64_t)m;
    int64_t b = mm;
    int64_t u = 1;
    int64_t v = 0;

    while (b != 0) {
        const int64_t t = aa / b;

        aa -= t * b;
        SWAP(uint64_t, aa, b);
        u -= t * v;
        SWAP(uint64_t, u, v);
    }

    u %= mm;
    if (u < 0) {
        u += m;
    }

    return (uint64_t)u;
}

static size_t powSz(const size_t base, const size_t exp) {
    if (exp == 0) {
        return 1;
    }

    if (exp == 1) {
        return base;
    }

    if (exp % 2 == 0) {
        return powSz(base * base, exp / 2);
    }
    else {
        return base * powSz(base, exp - 1);
    }
}

static uint64_t powU64(const uint64_t base, const uint64_t exp) {
    if (exp == 0) {
        return 1;
    }

    if (exp == 1) {
        return base;
    }

    if (exp % 2 == 0) {
        return powU64(base * base, exp / 2);
    }
    else {
        return base * powU64(base, exp - 1);
    }
}

static uint64_t powU64WMod(const uint64_t base, const uint64_t exp, const uint64_t m) {
    if (exp == 0) {
        return 1;
    }

    if (exp == 1) {
        return base % m;
    }

    if (exp % 2 == 0) {
        return powU64WMod(base * base % m, exp / 2, m);
    }
    else {
        return base * powU64WMod(base, exp - 1, m) % m;
    }
}

static size_t comb(const size_t n, const size_t r) {
    size_t result = 1;

    for (size_t i = 0; i < r; i++) {
        result *= n - i;
        result /= i + 1;
    }

    return result;
}

static uint64_t combU64(const uint64_t n, const uint64_t r) {
    uint64_t result = 1;

    for (uint64_t i = 0; i < r; i++) {
        result *= n - i;
        result /= i + 1;
    }

    return result;
}

static uint64_t combU64WMod(const uint64_t n, const uint64_t r, const uint64_t m) {
    uint64_t result = 1;
    uint64_t inv = 1;

    for (uint64_t i = 0; i < r; i++) {
        result = result * (n - i) % m;
        inv = inv * (i + 1) % m;
    }

    return result * modinvU64(inv, m) % m;
}

static uint64_t permU64WMod(const uint64_t n, const uint64_t m) {
    uint64_t result = 1;

    for (uint64_t v = 2; v <= n; v++) {
        result *= v;
        result %= m;
    }

    return result;
}

static size_t gcdZu(size_t m, size_t n) {
    size_t temp;

    while (m % n != 0) {
        temp = n;
        n = m % n;
        m = temp;
    }

    return n;
}

static uint64_t gcdU64(uint64_t m, uint64_t n)
{
    uint64_t temp;

    while (m % n != 0) {
        temp = n;
        n = m % n;
        m = temp;
    }

    return n;
}

typedef struct {
    uint64_t val;
}BHeap_Val;

#define BHEAP_VAL_TYPE BHeap_Val

#define BHEAP_INVALID_NODE ((size_t)100000000)

typedef struct {
    BHEAP_VAL_TYPE val;
} BHeap_Node;


struct _BHeap_Ctx {
    size_t size;
    int (*compare)(const BHEAP_VAL_TYPE* parent, const BHEAP_VAL_TYPE* node);
    void(*notifyNodeChange)(const struct _BHeap_Ctx* const ctx, const size_t nodeListSize, const size_t* const nodeList);
    BHeap_Node* node;
};

typedef struct _BHeap_Ctx BHeap_Ctx;

static void bHeap_Init(BHeap_Ctx* const ctx, int(*compare)(const BHEAP_VAL_TYPE* parent, const BHEAP_VAL_TYPE* node), void(*notifyNodeChange)(const BHeap_Ctx* const ctx, const size_t nodeListSize, const size_t* const nodeList), BHeap_Node* const nodes) {
    ctx->size = 0;
    ctx->compare = compare;
    ctx->notifyNodeChange = notifyNodeChange;
    ctx->node = nodes;
}

static void bHeap_Swap(BHeap_Ctx* const ctx, const size_t node0, const size_t node1) {
    const BHEAP_VAL_TYPE tmp = ctx->node[node0].val;
    ctx->node[node0].val = ctx->node[node1].val;
    ctx->node[node1].val = tmp;

    if (ctx->notifyNodeChange != NULL) {
        const size_t nodeList[2] = { node0,node1 };
        ctx->notifyNodeChange(ctx, 2, nodeList);
    }
}

static void bHeap_UpHeap(BHeap_Ctx* const ctx, const size_t nodeIdx) {
    if (nodeIdx == 0) {
        return;
    }

    const size_t parentIdx = (nodeIdx + 1) / 2 - 1;

    const int compareResult = ctx->compare(&(ctx->node[parentIdx].val), &(ctx->node[nodeIdx].val));

    if (0 < compareResult) {
        bHeap_Swap(ctx, nodeIdx, parentIdx);

        if (parentIdx != 0) {
            bHeap_UpHeap(ctx, parentIdx);
        }
    }
}

static void bHeap_DownHeap(BHeap_Ctx* const ctx, const size_t nodeIdx) {
    if (ctx->size - 1 <= nodeIdx) {
        return;
    }

    const size_t leftIdx = 2 * (nodeIdx + 1) - 1;

    if (leftIdx < ctx->size) {
        const int leftResult = ctx->compare(&(ctx->node[nodeIdx].val), &(ctx->node[leftIdx].val));

        size_t swapTarget = leftResult < 0 ? BHEAP_INVALID_NODE : leftIdx;

        const size_t rightIdx = leftIdx + 1;

        if (rightIdx < ctx->size) {
            const int rightResult = ctx->compare(&(ctx->node[nodeIdx].val), &(ctx->node[rightIdx].val));

            if (swapTarget == BHEAP_INVALID_NODE) {
                if (0 < rightResult) {
                    swapTarget = rightIdx;
                }
            }
            else {
                if (0 < rightResult) {
                    const int rightLeftResult = ctx->compare(&(ctx->node[leftIdx].val), &(ctx->node[rightIdx].val));

                    if (0 < rightLeftResult) {
                        swapTarget = rightIdx;
                    }
                }
            }
        }

        if (swapTarget != BHEAP_INVALID_NODE) {
            bHeap_Swap(ctx, nodeIdx, swapTarget);

            bHeap_DownHeap(ctx, swapTarget);
        }
    }
}

static void bHeap_Add(BHeap_Ctx* const ctx, const BHEAP_VAL_TYPE val) {
    ctx->node[ctx->size].val = val;

    ctx->size++;

    if (ctx->notifyNodeChange != NULL) {
        const size_t node = ctx->size - 1;
        ctx->notifyNodeChange(ctx, 1, &node);
    }

    bHeap_UpHeap(ctx, ctx->size - 1);
}

static void bHeap_RemoveTop(BHeap_Ctx* const ctx) {
    if (ctx->size == 0) {
        return;
    }

    if (ctx->size == 1) {
        ctx->size--;
        return;
    }

    ctx->node[0].val = ctx->node[ctx->size - 1].val;

    if (ctx->notifyNodeChange != NULL) {
        const size_t node = 0;
        ctx->notifyNodeChange(ctx, 1, &node);
    }

    ctx->size--;

    bHeap_DownHeap(ctx, 0);
}

static void bHeap_RemoveNode(BHeap_Ctx* const ctx, const size_t node) {
    if (node == ctx->size - 1) {
        ctx->size--;
    }
    else {
        ctx->node[node].val = ctx->node[ctx->size - 1].val;

        ctx->size--;

        if (ctx->notifyNodeChange != NULL) {
            ctx->notifyNodeChange(ctx, 1, &node);
        }

        bHeap_DownHeap(ctx, node);
        bHeap_UpHeap(ctx, node);
    }
}

static BHEAP_VAL_TYPE* bHeap_GetTopVal(const BHeap_Ctx* const ctx) {
    return ctx->size == 0 ? NULL : &(ctx->node[0].val);
}

typedef struct {
    uint64_t cnt;
    size_t* child;
    size_t numChild;
    size_t maxNumChild;
} Tree_Node;

#define TREE_INIT_ALLOC (128)

static Tree_Node tree_Node[200000];

static void tree_Init(const uint64_t N) {
    for (uint64_t i = 0; i < N; i++) {
        tree_Node[i].cnt = 0;
        tree_Node[i].numChild = 0;
        tree_Node[i].child = malloc(sizeof(size_t) * TREE_INIT_ALLOC);
        tree_Node[i].maxNumChild = TREE_INIT_ALLOC;
    }
}

static void tree_AddChild(const size_t parent, const size_t child) {
    if (tree_Node[parent].maxNumChild <= tree_Node[parent].numChild) {
        tree_Node[parent].child = realloc(tree_Node[parent].child, sizeof(size_t) * tree_Node[parent].maxNumChild * 2);
        tree_Node[parent].maxNumChild *= 2;
    }

    tree_Node[parent].child[tree_Node[parent].numChild] = child;
    tree_Node[parent].numChild++;
}

static BHeap_Node BN_Asc[200000];
static BHeap_Node BN_Desc[200000];

static int _bHeap_Compare_Asc(const BHEAP_VAL_TYPE* parent, const BHEAP_VAL_TYPE* node) {
    return parent->val <= node->val ? -1 : 1;
}

static int _bHeap_Compare_Desc(const BHEAP_VAL_TYPE* parent, const BHEAP_VAL_TYPE* node) {
    return parent->val >= node->val ? -1 : 1;
}

static size_t PBHeap_Asc_Idx[200000];
static size_t PBHeap_Desc_Idx[200000];

static void _bHeap_NotifyNodeChange_Asc(const BHeap_Ctx* const ctx, const size_t nodeListSize, const size_t* const nodeList) {
    for (size_t i = 0; i < nodeListSize; i++) {
        PBHeap_Asc_Idx[ctx->node[nodeList[i]].val.val] = nodeList[i];
    }
}

static void _bHeap_NotifyNodeChange_Desc(const BHeap_Ctx* const ctx, const size_t nodeListSize, const size_t* const nodeList) {
    for (size_t i = 0; i < nodeListSize; i++) {
        PBHeap_Desc_Idx[ctx->node[nodeList[i]].val.val] = nodeList[i];
    }
}

#define MOD_VAL (UINT64_C(1000000007))

#define UF_ROOT ((size_t)10000000)

typedef struct {
    size_t parent;
    uint64_t w;
    uint64_t v;
    uint64_t wSum;
    uint64_t vSum;
} UF_Node;

static UF_Node uf_Node[101];

static size_t uf_GetRoot(const size_t idx) {
    if (uf_Node[idx].parent == UF_ROOT) {
        return idx;
    }

    const size_t root = uf_GetRoot(uf_Node[idx].parent);

    uf_Node[idx].parent = root;

    return root;
}

static void uf_Merge(const size_t a, const size_t b) {
    const size_t aRoot = uf_GetRoot(a);
    const size_t bRoot = uf_GetRoot(b);

    if (aRoot != bRoot) {
        uf_Node[aRoot].parent = bRoot;

        uf_Node[bRoot].wSum += uf_Node[aRoot].wSum;
        uf_Node[bRoot].vSum += uf_Node[aRoot].vSum;
    }
}

typedef struct {
    uint64_t A;
    uint64_t B;
} MI;

static MI mi[3000];

static int compare_f(const void* a, const void* b) {
    return ((MI*)a)->A <= ((MI*)b)->A ? -1 : 1;
}

static uint64_t dp[6000];

int main(void) {
    uint64_t N,T;

    scanf("%"PRIu64"%"PRIu64, &N, &T);

    for (uint64_t i = 0; i < T + 3000; i++) {
        dp[i] = 0;
    }

    for (uint64_t i = 0; i < N; i++) {
        scanf("%"PRIu64"%"PRIu64, &mi[i].A, &mi[i].B);
    }

    qsort(mi, (size_t)N, sizeof(MI), compare_f);

    uint64_t dMax = 0;

    for (uint64_t i = 0; i < N; i++) {
        for (uint64_t tOfs = 0; tOfs < T; tOfs++) {
            const uint64_t t = T - tOfs - 1;

            dp[t + mi[i].A] = MAX(dp[t] + mi[i].B, dp[t + mi[i].A]);

            if (dMax < dp[t + mi[i].A]) {
                dMax = dp[t + mi[i].A];
            }
        }
    }

    printf("%"PRIu64"\n", dMax);


    return 0;
}