N, M = map(int, input().split())
gems = []
for _ in range(N):
    v, w = map(int, input().split())
    gems.append((v, w))

# Sort gems in descending order of value; if values are equal, order by weight (order doesn't matter)
gems.sort(key=lambda x: (-x[0], x[1]))

# Preprocess the dp list where dp[i] represents the DP array for the first i-1 gems (0-based)
dp_prev = [0] * (M + 1)
dp_list = [dp_prev.copy()]

for i in range(N):
    v, w = gems[i]
    new_dp = dp_prev.copy()
    for j in range(M, w - 1, -1):
        if new_dp[j - w] + v > new_dp[j]:
            new_dp[j] = new_dp[j - w] + v
    dp_list.append(new_dp)
    dp_prev = new_dp

max_g = 0
for i in range(N):
    v_i, w_i = gems[i]
    if w_i > M:
        continue
    remaining = M - w_i
    if remaining < 0:
        continue
    sum_rest = dp_list[i][remaining]  # dp_list[i] uses the first i-1 gems (0-based)
    total = v_i + sum_rest
    current_g = v_i * total
    if current_g > max_g:
        max_g = current_g

print(max_g)