import sys
#input = sys.stdin.readline
input = sys.stdin.buffer.readline #文字列はダメ
#sys.setrecursionlimit(1000000)
#import bisect
#import itertools
#import random
#from heapq import heapify, heappop, heappush
#from collections import defaultdict 
#from collections import deque
#import copy
#import math
#from functools import lru_cache
#@lru_cache(maxsize=None)
#MOD = pow(10,9) + 7
#MOD = 998244353
#dx = [1,0,-1,0]
#dy = [0,1,0,-1]

def main():
    N,M = map(int,input().split()); INF = pow(10,18)
    V = []; W = []; Z = []
    for i in range(N):
        v,w = map(int,input().split())
        V.append(v)
        W.append(w)
        Z.append((v,w))
    #宝石がの美しさが大きい順
    Z.sort(reverse=True)
    #print(Z)
    #dp[i][j]:i番目を使って重さがjの時の美しさの総和の最大値
    dp = [[-INF]*(M+1) for _ in range(N+1)]
    dp[0][0] = 0
    #dps[i]:i番以下における重さがjの時の美しさの総和最大値
    dps = [[-INF]*(M+1) for _ in range(N+1)]
    dps[0][0] = 0
    for i in range(N):
        vi = Z[i][0]; wi = Z[i][1]
        #print(vi,wi)
        for j in range(M+1):
            nj = j + wi
            if nj <= M:
                dp[i+1][nj] = max(dp[i+1][nj], dps[i][j] + vi)
        for j in range(M+1):
            dps[i+1][j] = max(dps[i][j], dp[i+1][j])
        #print(dp[i+1])
        #print(dps[i+1])
    ans = 0
    for i in range(N):
        for j in range(M+1):
            temp = dp[i+1][j] * Z[i][0]
            ans = max(ans, temp)
    print(ans)

if __name__ == '__main__':
    main()