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

vw =[]
for i in range(n):
    v, w = map(int, input().split())
    vw.append([v, w])

vw.sort(key=lambda x: x[0], reverse=True)

dp = [[-1] * (m+1) for _ in range(n+1)]

dp[0][0] = 0

ans = 0

for i in range(n):
    v, w = vw[i]
    for j in range(m+1):
        if dp[i][j] < 0:
            continue

        dp[i+1][j] = max(dp[i+1][j], dp[i][j])

        if j+w < m:
            dp[i+1][j+w] = max(dp[i+1][j+w], dp[i][j] + v)
            ans = max(ans, v * dp[i+1][j+w])

print(ans)