import sys
input = sys.stdin.readline

N,I=map(int,input().split())
SA=[tuple(map(int,input().split())) for i in range(N)]

DP=[0]*1010

for s,a in SA:
    for i in range(1009,-1,-1):
        if s+i<1010:
            DP[s+i]=max(DP[i]+a,DP[s+i])

print(max(DP[:I+1]))