N, M = map(int, input().split())
items = []
for i in range(N):
    V, W = map(int, input().split())
    items.append((V, W))


def knapsack(min_v):
    dp = [-1] * (M+1)
    dp[0] = 0
    for v, w in items:
        if v < min_v: continue
        for i in reversed(range(M)):
            if dp[i] == -1: continue
            if i+w > M: continue
            dp[i+w] = max(dp[i+w], dp[i] + v)

    return max(dp)


vset = set(v for v, _ in items)
ans = 0
for v in vset:
    ans = max(ans, v * knapsack(v))

print(ans)