LIMIT = 1001001
INF = 10**18

N, W = [int(s) for s in input().split()]
v_list, w_list = [0] * N, [0] * N

for i in range(N):
    v_list[i], w_list[i] = [int(s) for s in input().split()]

dp = [-INF] * LIMIT
dp[0] = 0

for v, w in zip(v_list, w_list):
    for i in range(LIMIT):
        if i - w >= 0:
            dp[i] = max(dp[i - w] + v, dp[i])

max_idx = max(range(N), key=lambda i: v_list[i] / w_list[i])
v, w = v_list[max_idx], w_list[max_idx]

ans = 0

for i in range(min(LIMIT, W + 1)):
    ans = max(dp[i] + v * ((W - i) // w), ans)

print(ans)