import sys

# sys.setrecursionlimit(200005)
# sys.set_int_max_str_digits(200005)
int1 = lambda x: int(x)-1
pDB = lambda *x: print(*x, end="\n", file=sys.stderr)
p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr)
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()

# dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
# inf = -1-(-1 << 31)
# inf = -1-(-1 << 62)

# md = 10**9+7
md = 998244353

N,M=LI()
vw=LLI(N)
vw.sort(key=lambda x:-x[0])
ans=0
dp=[0]*(M+1)
for v,w in vw:
    for i in range(M-w,-1,-1):
        dp[i+w]=max(dp[i+w],dp[i]+v)
    ans=max(ans,dp[M]*v)

print(ans)