import numpy as np
import sys
input = sys.stdin.buffer.readline
inf = 10**18

N, K = map(int, input().split())
PD = list(tuple(map(int, input().split())) for _ in range(N))
PD.sort(reverse=True)

dp0 = np.full(K + 1, -inf, dtype=np.int64)
dp1 = np.full_like(dp0, -inf)
dp0[0] = 0

for p, d in PD:
    newDP0 = np.copy(dp0)
    newDP1 = np.copy(dp1)
    newDP1[p:] = np.maximum(newDP1[p:], dp0[:-p] + d)
    newDP0 = np.maximum(newDP0, dp1 + d)
    dp0 = newDP0
    dp1 = newDP1

ans = max(dp0.max(), dp1.max())
print(ans)