## https://yukicoder.me/problems/no/3401

from functools import cmp_to_key

def compare_items(a, b):
    if a[1] * b[0] > a[0] * b[1]:
        return 1
    elif a[1] * b[0] < a[0] * b[1]:
        return -1
    else:
        return 0




def main():
    N, W = map(int, input().split())
    vw = []
    max_w = 0
    for _ in range(N):
        v, w = map(int, input().split())
        vw.append((v, w))
        max_w = max(max_w, w)
    
    k = (max_w + 1) ** 2
    if k < W:
        dp = [0] * (max_w + 1)
        dp[0] = 0
        for k in range(max_w + 1):
            if dp[k] == -1:
                continue

            for v, w in vw:
                if k + w <= max_w:
                    dp[k + w] = max(dp[k + w], dp[k] + v)
        

        # カスタム比較関数を使ってリストをソート
        sorted_vw = sorted(vw, key=cmp_to_key(compare_items))
        v0, w0 = sorted_vw[0]
        answer = -1
        for k in range(max_w + 1):
            if dp[k] == -1:
                continue

            x = W - k
            if x < 0:
                continue

            y = x // w0
            ans = dp[k] + y * v0
            answer = max(ans, answer)
        print(answer)
    else:
        dp = [-1] * (W + 1)
        dp[0] = 0
        answer = 0
        for k in range(W + 1):
            if dp[k] == -1:
                continue

            answer = max(answer, dp[k])
            for v, w in vw:
                if k + w <= W:
                    dp[k + w] = max(dp[k + w], dp[k] + v)
        print(answer)



if __name__ == '__main__':
    main()