n,l=map(int,input().split())

dp = [-1]*(l+1)
dp[0] = 0

for i in range(n):
    s,a=map(int,input().split())
    for j in range(l,0,-1):
        if j - s >= 0 and dp[j-s] != -1:
            dp[j] = dp[j-s] + a
            
print(max(dp))