# translated sclara's c++ code into Python by ChatGPT 5.1 Thinking

import sys

def main():
    data = list(map(int, sys.stdin.read().split()))
    it = iter(data)

    N = next(it)
    W = next(it)

    v = [0] * N
    w = [0] * N

    for i in range(N):
        v[i] = next(it)
        w[i] = next(it)

    ans = 0

    bestv = v[0]
    bestw = w[0]
    maxw = w[0]

    for i in range(1, N):
        if bestv * w[i] < v[i] * bestw:
            bestv = v[i]
            bestw = w[i]
        if maxw < w[i]:
            maxw = w[i]

    least = (W - bestw * maxw + bestw) // bestw

    dp_size = bestw * maxw
    dp = [0] * dp_size

    for i in range(1, dp_size):
        for j in range(N):
            if w[j] <= i and dp[i] < dp[i - w[j]] + v[j]:
                dp[i] = dp[i - w[j]] + v[j]

    ans = least * bestv + dp[W - least * bestw]

    print(ans)


if __name__ == "__main__":
    main()